Class: IO
Overview
The IO class is the basis for all input and output in Ruby. An I/O stream may be duplexed (that is, bidirectional), and so may use more than one native operating system stream.
Many of the examples in this section use the File class, the only standard subclass of IO. The two classes are closely associated. Like the File class, the Socket library subclasses from IO (such as TCPSocket or UDPSocket).
The Kernel#open method can create an IO (or File) object for these types of arguments:
-
A plain string represents a filename suitable for the underlying operating system.
-
A string starting with
"|"
indicates a subprocess. The remainder of the string following the"|"
is invoked as a process with appropriate input/output channels connected to it. -
A string equal to
"|-"
will create another Ruby instance as a subprocess.
The IO may be opened with different file modes (read-only, write-only) and encodings for proper conversion. See IO.new for these options. See Kernel#open for details of the various command formats described above.
IO.popen, the Open3 library, or Process#spawn may also be used to communicate with subprocesses through an IO.
Ruby will convert pathnames between different operating system conventions if possible. For instance, on a Windows system the filename "/gumby/ruby/test.rb"
will be opened as "\gumby\ruby\test.rb"
. When specifying a Windows-style filename in a Ruby string, remember to escape the backslashes:
"C:\\gumby\\ruby\\test.rb"
Our examples here will use the Unix-style forward slashes; File::ALT_SEPARATOR can be used to get the platform-specific separator character.
The global constant ARGF (also accessible as $<
) provides an IO-like stream which allows access to all files mentioned on the command line (or STDIN if no files are mentioned). ARGF#path and its alias ARGF#filename are provided to access the name of the file currently being read.
io/console
The io/console extension provides methods for interacting with the console. The console can be accessed from IO.console or the standard input/output/error IO objects.
Requiring io/console adds the following methods:
-
IO::console
-
IO#raw
-
IO#raw!
-
IO#cooked
-
IO#cooked!
-
IO#getch
-
IO#echo=
-
IO#echo?
-
IO#noecho
-
IO#winsize
-
IO#winsize=
-
IO#iflush
-
IO#ioflush
-
IO#oflush
Example:
require 'io/console'
rows, columns = $stdout.winsize
puts "Your screen is #{columns} wide and #{rows} tall"
Direct Known Subclasses
Defined Under Namespace
Modules: WaitReadable, WaitWritable Classes: EAGAINWaitReadable, EAGAINWaitWritable, EINPROGRESSWaitReadable, EINPROGRESSWaitWritable, EWOULDBLOCKWaitReadable, EWOULDBLOCKWaitWritable
Constant Summary collapse
- READABLE =
INT2NUM(RUBY_IO_READABLE)
- WRITABLE =
INT2NUM(RUBY_IO_WRITABLE)
- PRIORITY =
INT2NUM(RUBY_IO_PRIORITY)
- SEEK_SET =
Set I/O position from the beginning
INT2FIX(SEEK_SET)
- SEEK_CUR =
Set I/O position from the current position
INT2FIX(SEEK_CUR)
- SEEK_END =
Set I/O position from the end
INT2FIX(SEEK_END)
- SEEK_DATA =
Set I/O position to the next location containing data
INT2FIX(SEEK_DATA)
- SEEK_HOLE =
Set I/O position to the next hole
INT2FIX(SEEK_HOLE)
Constants included from File::Constants
File::Constants::APPEND, File::Constants::BINARY, File::Constants::CREAT, File::Constants::DIRECT, File::Constants::DSYNC, File::Constants::EXCL, File::Constants::LOCK_EX, File::Constants::LOCK_NB, File::Constants::LOCK_SH, File::Constants::LOCK_UN, File::Constants::NOATIME, File::Constants::NOCTTY, File::Constants::NOFOLLOW, File::Constants::NONBLOCK, File::Constants::NULL, File::Constants::RDONLY, File::Constants::RDWR, File::Constants::RSYNC, File::Constants::SHARE_DELETE, File::Constants::SYNC, File::Constants::TMPFILE, File::Constants::TRUNC, File::Constants::WRONLY
Class Method Summary collapse
-
.binread(name, [length [, offset]]) ⇒ String
Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file).
-
.binwrite(*args) ⇒ Object
Same as IO.write except opening the file in binary mode and ASCII-8BIT encoding (
"wb:ASCII-8BIT"
). -
.copy_stream(*args) ⇒ Object
IO.copy_stream copies src to dst.
-
.for_fd(fd, mode[, opt]) ⇒ IO
Synonym for IO.new.
-
.foreach(*args) ⇒ Object
Executes the block for every line in the named I/O port, where lines are separated by sep.
-
.new(*args) ⇒ Object
:nodoc:.
-
.open(*args) ⇒ Object
call-seq: IO.open(fd, mode=“r” [, opt]) -> io IO.open(fd, mode=“r” [, opt]) {|io| block } -> obj.
-
.pipe(*args) ⇒ Object
IO.pipe(…) {|read_io, write_io| … }.
-
.popen(*args) ⇒ Object
Runs the specified command as a subprocess; the subprocess’s standard input and output will be connected to the returned IO object.
-
.read(name, [length [, offset]][, opt]) ⇒ String
Opens the file, optionally seeks to the given
offset
, then returnslength
bytes (defaulting to the rest of the file). -
.readlines(*args) ⇒ Object
Reads the entire file specified by name as individual lines, and returns those lines in an array.
-
.select(read_array[, write_array [, error_array [, timeout]]]) ⇒ Array?
Calls select(2) system call.
-
.sysopen(path, [mode, [perm]]) ⇒ Integer
Opens the given path, returning the underlying file descriptor as a Integer.
-
.try_convert(obj) ⇒ IO?
Try to convert obj into an IO, using to_io method.
-
.write(*args) ⇒ Object
Opens the file, optionally seeks to the given offset, writes string, then returns the length written.
Instance Method Summary collapse
-
#<<(obj) ⇒ IO
String Output—Writes obj to ios.
-
#advise(advice, offset = 0, len = 0) ⇒ nil
Announce an intention to access data from the current file in a specific pattern.
-
#autoclose=(bool) ⇒ Boolean
Sets auto-close flag.
-
#autoclose? ⇒ Boolean
Returns
true
if the underlying file descriptor of ios will be closed automatically at its finalization, otherwisefalse
. -
#binmode ⇒ IO
Puts ios into binary mode.
-
#binmode? ⇒ Boolean
Returns
true
if ios is binmode. -
#close ⇒ nil
Closes ios and flushes any pending writes to the operating system.
-
#close_on_exec=(bool) ⇒ Boolean
Sets a close-on-exec flag.
-
#close_on_exec? ⇒ Boolean
Returns
true
if ios will be closed on exec. -
#close_read ⇒ nil
Closes the read end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe).
-
#close_write ⇒ nil
Closes the write end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe).
-
#closed? ⇒ Boolean
Returns
true
if ios is completely closed (for duplex streams, both reader and writer),false
otherwise. -
#each(*args) ⇒ Object
ios.each_line(sep=$/ [, getline_args]) {|line| block } -> ios ios.each_line(limit [, getline_args]) {|line| block } -> ios ios.each_line(sep, limit [, getline_args]) {|line| block } -> ios ios.each_line(…) -> an_enumerator.
-
#each_byte ⇒ Object
Calls the given block once for each byte (0..255) in ios, passing the byte as an argument.
-
#each_char ⇒ Object
Calls the given block once for each character in ios, passing the character as an argument.
-
#each_codepoint ⇒ Object
Passes the Integer ordinal of each character in ios, passing the codepoint as an argument.
-
#each_line(*args) ⇒ Object
ios.each_line(sep=$/ [, getline_args]) {|line| block } -> ios ios.each_line(limit [, getline_args]) {|line| block } -> ios ios.each_line(sep, limit [, getline_args]) {|line| block } -> ios ios.each_line(…) -> an_enumerator.
-
#eof ⇒ Object
Returns true if ios is at end of file that means there are no more data to read.
-
#eof? ⇒ Object
Returns true if ios is at end of file that means there are no more data to read.
-
#external_encoding ⇒ Encoding
Returns the Encoding object that represents the encoding of the file.
-
#fcntl(integer_cmd, arg) ⇒ Integer
Provides a mechanism for issuing low-level commands to control or query file-oriented I/O streams.
-
#fdatasync ⇒ 0?
Immediately writes all buffered data in ios to disk.
-
#fileno ⇒ Object
(also: #to_i)
Returns an integer representing the numeric file descriptor for ios.
-
#flush ⇒ IO
Flushes any buffered data within ios to the underlying operating system (note that this is Ruby internal buffering only; the OS may buffer the data as well).
-
#fsync ⇒ 0?
Immediately writes all buffered data in ios to disk.
-
#getbyte ⇒ Integer?
Gets the next 8-bit byte (0..255) from ios.
-
#getc ⇒ String?
Reads a one-character string from ios.
-
#gets(*args) ⇒ Object
Reads the next “line” from the I/O stream; lines are separated by sep.
-
#new(fd[, mode][, opt]) ⇒ IO
constructor
Returns a new IO object (a stream) for the given integer file descriptor
fd
andmode
string. -
#initialize_copy(io) ⇒ Object
:nodoc:.
-
#inspect ⇒ String
Return a string describing this IO object.
-
#internal_encoding ⇒ Encoding
Returns the Encoding of the internal string if conversion is specified.
-
#ioctl(integer_cmd, arg) ⇒ Integer
Provides a mechanism for issuing low-level commands to control or query I/O devices.
-
#isatty ⇒ Object
Returns
true
if ios is associated with a terminal device (tty),false
otherwise. -
#lineno ⇒ Integer
Returns the current line number in ios.
-
#lineno=(integer) ⇒ Integer
Manually sets the current line number to the given value.
-
#pid ⇒ Integer
Returns the process ID of a child process associated with ios.
-
#pos ⇒ Object
Returns the current offset (in bytes) of ios.
-
#pos=(integer) ⇒ Integer
Seeks to the given position (in bytes) in ios.
-
#pread(maxlen, offset[, outbuf]) ⇒ String
Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset.
-
#print(*args) ⇒ Object
Writes the given object(s) to ios.
-
#printf(format_string[, obj, ...]) ⇒ nil
Formats and writes to ios, converting parameters under control of the format string.
-
#putc(obj) ⇒ Object
If obj is Numeric, write the character whose code is the least-significant byte of obj.
-
#puts(obj, ...) ⇒ nil
Writes the given object(s) to ios.
-
#pwrite(string, offset) ⇒ Integer
Writes the given string to ios at offset using pwrite() system call.
-
#read([length [, outbuf]]) ⇒ String?
Reads length bytes from the I/O stream.
-
#readbyte ⇒ Integer
Reads a byte as with IO#getbyte, but raises an EOFError on end of file.
-
#readchar ⇒ String
Reads a one-character string from ios.
-
#readline(*args) ⇒ Object
Reads a line as with IO#gets, but raises an EOFError on end of file.
-
#readlines(*args) ⇒ Object
Reads all of the lines in ios, and returns them in an array.
-
#readpartial(*args) ⇒ Object
Reads at most maxlen bytes from the I/O stream.
-
#reopen(*args) ⇒ Object
Reassociates ios with the I/O stream given in other_IO or to a new stream opened on path.
-
#rewind ⇒ 0
Positions ios to the beginning of input, resetting #lineno to zero.
-
#seek(amount, whence = IO::SEEK_SET) ⇒ 0
Seeks to a given offset anInteger in the stream according to the value of whence:.
-
#set_encoding(*args) ⇒ Object
If single argument is specified, read string from io is tagged with the encoding specified.
-
#set_encoding_by_bom ⇒ Encoding?
Checks if
ios
starts with a BOM, and then consumes it and sets the external encoding. -
#stat ⇒ Object
Returns status information for ios as an object of type File::Stat.
-
#sync ⇒ Boolean
Returns the current “sync mode” of ios.
- #sync=(sync) ⇒ Object
-
#sysread(maxlen[, outbuf]) ⇒ String
Reads maxlen bytes from ios using a low-level read and returns them as a string.
-
#sysseek(offset, whence = IO::SEEK_SET) ⇒ Integer
Seeks to a given offset in the stream according to the value of whence (see IO#seek for values of whence).
-
#syswrite(string) ⇒ Integer
Writes the given string to ios using a low-level write.
-
#tell ⇒ Object
Returns the current offset (in bytes) of ios.
-
#to_io ⇒ IO
Returns ios.
-
#tty? ⇒ Object
Returns
true
if ios is associated with a terminal device (tty),false
otherwise. -
#ungetbyte(b) ⇒ Object
Pushes back bytes (passed as a parameter) onto ios, such that a subsequent buffered read will return it.
-
#ungetc(string) ⇒ nil
Pushes back one character (passed as a parameter) onto ios, such that a subsequent buffered character read will return it.
-
#write(string, ...) ⇒ Integer
Writes the given strings to ios.
Methods included from Enumerable
#all?, #any?, #chain, #chunk, #chunk_while, #collect, #collect_concat, #count, #cycle, #detect, #drop, #drop_while, #each_cons, #each_entry, #each_slice, #each_with_index, #each_with_object, #entries, #filter, #filter_map, #find, #find_all, #find_index, #first, #flat_map, #grep, #grep_v, #group_by, #include?, #inject, #lazy, #map, #max, #max_by, #member?, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #reject, #reverse_each, #select, #slice_after, #slice_before, #slice_when, #sort, #sort_by, #sum, #take, #take_while, #tally, #to_a, #to_h, #uniq, #zip
Constructor Details
#new(fd[, mode][, opt]) ⇒ IO
Returns a new IO object (a stream) for the given integer file descriptor fd
and mode
string. opt
may be used to specify parts of mode
in a more readable fashion. See also IO.sysopen and IO.for_fd.
IO.new is called by various File and IO opening methods such as IO::open, Kernel#open, and File::open.
Open Mode
When mode
is an integer it must be combination of the modes defined in File::Constants (File::RDONLY
, File::WRONLY|File::CREAT
). See the open(2) man page for more information.
When mode
is a string it must be in one of the following forms:
fmode
fmode ":" ext_enc
fmode ":" ext_enc ":" int_enc
fmode ":" "BOM|UTF-*"
fmode
is an IO open mode string, ext_enc
is the external encoding for the IO and int_enc
is the internal encoding.
IO Open Mode
Ruby allows the following open modes:
“r” Read-only, starts at beginning of file (default mode).
“r+” Read-write, starts at beginning of file.
“w” Write-only, truncates existing file to zero length or creates a new file for writing.
“w+” Read-write, truncates existing file to zero length or creates a new file for reading and writing.
“a” Write-only, each write call appends data at end of file. Creates a new file for writing if file does not exist.
“a+” Read-write, each write call appends data at end of file.
Creates a new file for reading and writing if file does
not exist.
The following modes must be used separately, and along with one or more of the modes seen above.
“b” Binary file mode Suppresses EOL <-> CRLF conversion on Windows. And sets external encoding to ASCII-8BIT unless explicitly specified.
“t” Text file mode
The exclusive access mode (“x”) can be used together with “w” to ensure the file is created. Errno::EEXIST is raised when it already exists. It may not be supported with all kinds of streams (e.g. pipes).
When the open mode of original IO is read only, the mode cannot be changed to be writable. Similarly, the open mode cannot be changed from write only to readable.
When such a change is attempted the error is raised in different locations according to the platform.
IO Encoding
When ext_enc
is specified, strings read will be tagged by the encoding when reading, and strings output will be converted to the specified encoding when writing.
When ext_enc
and int_enc
are specified read strings will be converted from ext_enc
to int_enc
upon input, and written strings will be converted from int_enc
to ext_enc
upon output. See Encoding for further details of transcoding on input and output.
If “BOM|UTF-8”, “BOM|UTF-16LE” or “BOM|UTF16-BE” are used, Ruby checks for a Unicode BOM in the input document to help determine the encoding. For UTF-16 encodings the file open mode must be binary. When present, the BOM is stripped and the external encoding from the BOM is used. When the BOM is missing the given Unicode encoding is used as ext_enc
. (The BOM-set encoding option is case insensitive, so “bom|utf-8” is also valid.)
Options
opt
can be used instead of mode
for improved readability. The following keys are supported:
- :mode
-
Same as
mode
parameter - :flags
-
Specifies file open flags as integer. If
mode
parameter is given, this parameter will be bitwise-ORed. - :external_encoding
-
External encoding for the IO.
- :internal_encoding
-
Internal encoding for the IO. “-” is a synonym for the default internal encoding.
If the value is
nil
no conversion occurs. - :encoding
-
Specifies external and internal encodings as “extern:intern”.
- :textmode
-
If the value is truth value, same as “t” in argument
mode
. - :binmode
-
If the value is truth value, same as “b” in argument
mode
. - :autoclose
-
If the value is
false
, thefd
will be kept open after this IO instance gets finalized.
Also, opt
can have same keys in String#encode for controlling conversion between the external encoding and the internal encoding.
Example 1
fd = IO.sysopen("/dev/tty", "w")
a = IO.new(fd,"w")
$stderr.puts "Hello"
a.puts "World"
Produces:
Hello
World
Example 2
require 'fcntl'
fd = STDERR.fcntl(Fcntl::F_DUPFD)
io = IO.new(fd, mode: 'w:UTF-16LE', cr_newline: true)
io.puts "Hello, World!"
fd = STDERR.fcntl(Fcntl::F_DUPFD)
io = IO.new(fd, mode: 'w', cr_newline: true,
external_encoding: Encoding::UTF_16LE)
io.puts "Hello, World!"
Both of above print “Hello, World!” in UTF-16LE to standard error output with converting EOL generated by #puts to CR.
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# File 'io.c', line 8435
static VALUE
rb_io_initialize(int argc, VALUE *argv, VALUE io)
{
VALUE fnum, vmode;
rb_io_t *fp;
int fd, fmode, oflags = O_RDONLY;
convconfig_t convconfig;
VALUE opt;
#if defined(HAVE_FCNTL) && defined(F_GETFL)
int ofmode;
#else
struct stat st;
#endif
argc = rb_scan_args(argc, argv, "11:", &fnum, &vmode, &opt);
rb_io_extract_modeenc(&vmode, 0, opt, &oflags, &fmode, &convconfig);
fd = NUM2INT(fnum);
if (rb_reserved_fd_p(fd)) {
rb_raise(rb_eArgError, "The given fd is not accessible because RubyVM reserves it");
}
#if defined(HAVE_FCNTL) && defined(F_GETFL)
oflags = fcntl(fd, F_GETFL);
if (oflags == -1) rb_sys_fail(0);
#else
if (fstat(fd, &st) < 0) rb_sys_fail(0);
#endif
rb_update_max_fd(fd);
#if defined(HAVE_FCNTL) && defined(F_GETFL)
ofmode = rb_io_oflags_fmode(oflags);
if (NIL_P(vmode)) {
fmode = ofmode;
}
else if ((~ofmode & fmode) & FMODE_READWRITE) {
VALUE error = INT2FIX(EINVAL);
rb_exc_raise(rb_class_new_instance(1, &error, rb_eSystemCallError));
}
#endif
if (!NIL_P(opt) && rb_hash_aref(opt, sym_autoclose) == Qfalse) {
fmode |= FMODE_PREP;
}
MakeOpenFile(io, fp);
fp->self = io;
fp->fd = fd;
fp->mode = fmode;
fp->encs = convconfig;
clear_codeconv(fp);
io_check_tty(fp);
if (fileno(stdin) == fd)
fp->stdio_file = stdin;
else if (fileno(stdout) == fd)
fp->stdio_file = stdout;
else if (fileno(stderr) == fd)
fp->stdio_file = stderr;
if (fmode & FMODE_SETENC_BY_BOM) io_set_encoding_by_bom(io);
return io;
}
|
Class Method Details
.binread(name, [length [, offset]]) ⇒ String
Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). #binread ensures the file is closed before returning. The open mode would be "rb:ASCII-8BIT"
.
IO.binread("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
IO.binread("testfile", 20) #=> "This is line one\nThi"
IO.binread("testfile", 20, 10) #=> "ne one\nThis is line "
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# File 'io.c', line 10792
static VALUE
rb_io_s_binread(int argc, VALUE *argv, VALUE io)
{
VALUE offset;
struct foreach_arg arg;
enum {
fmode = FMODE_READABLE|FMODE_BINMODE,
oflags = O_RDONLY
#ifdef O_BINARY
|O_BINARY
#endif
};
convconfig_t convconfig = {NULL, NULL, 0, Qnil};
rb_scan_args(argc, argv, "12", NULL, NULL, &offset);
FilePathValue(argv[0]);
convconfig.enc = rb_ascii8bit_encoding();
arg.io = rb_io_open_generic(io, argv[0], oflags, fmode, &convconfig, 0);
if (NIL_P(arg.io)) return Qnil;
arg.argv = argv+1;
arg.argc = (argc > 1) ? 1 : 0;
if (!NIL_P(offset)) {
struct seek_arg sarg;
int state = 0;
sarg.io = arg.io;
sarg.offset = offset;
sarg.mode = SEEK_SET;
rb_protect(seek_before_access, (VALUE)&sarg, &state);
if (state) {
rb_io_close(arg.io);
rb_jump_tag(state);
}
}
return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}
|
.binwrite(name, string, [offset]) ⇒ Integer .binwrite(name, string, [offset], open_args) ⇒ Integer
Same as IO.write except opening the file in binary mode and ASCII-8BIT encoding ("wb:ASCII-8BIT"
).
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# File 'io.c', line 10941
static VALUE
rb_io_s_binwrite(int argc, VALUE *argv, VALUE io)
{
return io_s_write(argc, argv, io, 1);
}
|
.copy_stream(src, dst) ⇒ Object .copy_stream(src, dst, copy_length) ⇒ Object .copy_stream(src, dst, copy_length, src_offset) ⇒ Object
IO.copy_stream copies src to dst. src and dst is either a filename or an IO-like object. IO-like object for src should have #readpartial or #read method. IO-like object for dst should have #write method. (Specialized mechanisms, such as sendfile system call, may be used on appropriate situation.)
This method returns the number of bytes copied.
If optional arguments are not given, the start position of the copy is the beginning of the filename or the current file offset of the IO. The end position of the copy is the end of file.
If copy_length is given, No more than copy_length bytes are copied.
If src_offset is given, it specifies the start position of the copy.
When src_offset is specified and src is an IO, IO.copy_stream doesn’t move the current file offset.
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# File 'io.c', line 11876
static VALUE
rb_io_s_copy_stream(int argc, VALUE *argv, VALUE io)
{
VALUE src, dst, length, src_offset;
struct copy_stream_struct st;
MEMZERO(&st, struct copy_stream_struct, 1);
rb_scan_args(argc, argv, "22", &src, &dst, &length, &src_offset);
st.src = src;
st.dst = dst;
if (NIL_P(length))
st.copy_length = (off_t)-1;
else
st.copy_length = NUM2OFFT(length);
if (NIL_P(src_offset))
st.src_offset = (off_t)-1;
else
st.src_offset = NUM2OFFT(src_offset);
rb_ensure(copy_stream_body, (VALUE)&st, copy_stream_finalize, (VALUE)&st);
return OFFT2NUM(st.total);
}
|
.for_fd(fd, mode[, opt]) ⇒ IO
Synonym for IO.new.
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# File 'io.c', line 8599
static VALUE
rb_io_s_for_fd(int argc, VALUE *argv, VALUE klass)
{
VALUE io = rb_obj_alloc(klass);
rb_io_initialize(argc, argv, io);
return io;
}
|
.foreach(name, sep = $/[, getline_args, open_args]) {|line| ... } ⇒ nil .foreach(name, limit[, getline_args, open_args]) {|line| ... } ⇒ nil .foreach(name, sep, limit[, getline_args, open_args]) {|line| ... } ⇒ nil .foreach(...) ⇒ Object
Executes the block for every line in the named I/O port, where lines are separated by sep.
If no block is given, an enumerator is returned instead.
IO.foreach("testfile") {|x| print "GOT ", x }
produces:
GOT This is line one
GOT This is line two
GOT This is line three
GOT And so on...
If the last argument is a hash, it’s the keyword argument to open. See IO.readlines for details about getline_args. And see also IO.read for details about open_args.
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# File 'io.c', line 10619
static VALUE
rb_io_s_foreach(int argc, VALUE *argv, VALUE self)
{
VALUE opt;
int orig_argc = argc;
struct foreach_arg arg;
struct getline_arg garg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
RETURN_ENUMERATOR(self, orig_argc, argv);
extract_getline_args(argc-1, argv+1, &garg);
open_key_args(self, argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
extract_getline_opts(opt, &garg);
check_getline_args(&garg.rs, &garg.limit, garg.io = arg.io);
return rb_ensure(io_s_foreach, (VALUE)&garg, rb_io_close, arg.io);
}
|
.new(*args) ⇒ Object
:nodoc:
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# File 'io.c', line 8578
static VALUE
rb_io_s_new(int argc, VALUE *argv, VALUE klass)
{
if (rb_block_given_p()) {
VALUE cname = rb_obj_as_string(klass);
rb_warn("%"PRIsVALUE"::new() does not take block; use %"PRIsVALUE"::open() instead",
cname, cname);
}
return rb_class_new_instance_kw(argc, argv, klass, RB_PASS_CALLED_KEYWORDS);
}
|
.open(*args) ⇒ Object
call-seq:
IO.open(fd, mode="r" [, opt]) -> io
IO.open(fd, mode="r" [, opt]) {|io| block } -> obj
With no associated block, IO.open is a synonym for IO.new. If the optional code block is given, it will be passed io
as an argument, and the IO object will automatically be closed when the block terminates. In this instance, IO.open returns the value of the block.
See IO.new for a description of the fd
, mode
and opt
parameters.
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# File 'io.c', line 7157
static VALUE
rb_io_s_open(int argc, VALUE *argv, VALUE klass)
{
VALUE io = rb_class_new_instance_kw(argc, argv, klass, RB_PASS_CALLED_KEYWORDS);
if (rb_block_given_p()) {
return rb_ensure(rb_yield, io, io_close, io);
}
return io;
}
|
.pipe ⇒ Array .pipe(ext_enc) ⇒ Array .pipe("ext_enc: int_enc"[, opt]) ⇒ Array .pipe(ext_enc, int_enc[, opt]) ⇒ Array
IO.pipe(…) {|read_io, write_io| … }
Creates a pair of pipe endpoints (connected to each other) and returns them as a two-element array of IO objects: [
read_io, write_io ]
.
If a block is given, the block is called and returns the value of the block. read_io and write_io are sent to the block as arguments. If read_io and write_io are not closed when the block exits, they are closed. i.e. closing read_io and/or write_io doesn’t cause an error.
Not available on all platforms.
If an encoding (encoding name or encoding object) is specified as an optional argument, read string from pipe is tagged with the encoding specified. If the argument is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two optional arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.
In the example below, the two processes close the ends of the pipe that they are not using. This is not just a cosmetic nicety. The read end of a pipe will not generate an end of file condition if there are any writers with the pipe still open. In the case of the parent process, the rd.read
will never return if it does not first issue a wr.close
.
rd, wr = IO.pipe
if fork
wr.close
puts "Parent got: <#{rd.read}>"
rd.close
Process.wait
else
rd.close
puts "Sending message to parent"
wr.write "Hi Dad"
wr.close
end
produces:
Sending message to parent
Parent got: <Hi Dad>
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# File 'io.c', line 10460
static VALUE
rb_io_s_pipe(int argc, VALUE *argv, VALUE klass)
{
int pipes[2], state;
VALUE r, w, args[3], v1, v2;
VALUE opt;
rb_io_t *fptr, *fptr2;
struct io_encoding_set_args ies_args;
int fmode = 0;
VALUE ret;
argc = rb_scan_args(argc, argv, "02:", &v1, &v2, &opt);
if (rb_pipe(pipes) < 0)
rb_sys_fail(0);
args[0] = klass;
args[1] = INT2NUM(pipes[0]);
args[2] = INT2FIX(O_RDONLY);
r = rb_protect(io_new_instance, (VALUE)args, &state);
if (state) {
close(pipes[0]);
close(pipes[1]);
rb_jump_tag(state);
}
GetOpenFile(r, fptr);
ies_args.fptr = fptr;
ies_args.v1 = v1;
ies_args.v2 = v2;
ies_args.opt = opt;
rb_protect(io_encoding_set_v, (VALUE)&ies_args, &state);
if (state) {
close(pipes[1]);
io_close(r);
rb_jump_tag(state);
}
args[1] = INT2NUM(pipes[1]);
args[2] = INT2FIX(O_WRONLY);
w = rb_protect(io_new_instance, (VALUE)args, &state);
if (state) {
close(pipes[1]);
if (!NIL_P(r)) rb_io_close(r);
rb_jump_tag(state);
}
GetOpenFile(w, fptr2);
rb_io_synchronized(fptr2);
extract_binmode(opt, &fmode);
if ((fmode & FMODE_BINMODE) && v1 == Qnil) {
rb_io_ascii8bit_binmode(r);
rb_io_ascii8bit_binmode(w);
}
#if DEFAULT_TEXTMODE
if ((fptr->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
fptr->mode &= ~FMODE_TEXTMODE;
setmode(fptr->fd, O_BINARY);
}
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (fptr->encs.ecflags & ECONV_DEFAULT_NEWLINE_DECORATOR) {
fptr->encs.ecflags |= ECONV_UNIVERSAL_NEWLINE_DECORATOR;
}
#endif
#endif
fptr->mode |= fmode;
#if DEFAULT_TEXTMODE
if ((fptr2->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
fptr2->mode &= ~FMODE_TEXTMODE;
setmode(fptr2->fd, O_BINARY);
}
#endif
fptr2->mode |= fmode;
ret = rb_assoc_new(r, w);
if (rb_block_given_p()) {
VALUE rw[2];
rw[0] = r;
rw[1] = w;
return rb_ensure(rb_yield, ret, pipe_pair_close, (VALUE)rw);
}
return ret;
}
|
.popen([env,], mode = "r"[, opt]) ⇒ IO .popen([env,], mode = "r"[, opt]) {|io| ... } ⇒ Object
Runs the specified command as a subprocess; the subprocess’s standard input and output will be connected to the returned IO object.
The PID of the started process can be obtained by IO#pid method.
cmd is a string or an array as follows.
cmd:
"-" : fork
commandline : command line string which is passed to a shell
[env, cmdname, arg1, ..., opts] : command name and zero or more arguments (no shell)
[env, [cmdname, argv0], arg1, ..., opts] : command name, argv[0] and zero or more arguments (no shell)
(env and opts are optional.)
If cmd is a String
“-
”, then a new instance of Ruby is started as the subprocess.
If cmd is an Array
of String
, then it will be used as the subprocess’s argv
bypassing a shell. The array can contain a hash at first for environments and a hash at last for options similar to #spawn.
The default mode for the new file object is “r”, but mode may be set to any of the modes listed in the description for class IO. The last argument opt qualifies mode.
# set IO encoding
IO.popen("nkf -e filename", :external_encoding=>"EUC-JP") {|nkf_io|
euc_jp_string = nkf_io.read
}
# merge standard output and standard error using
# spawn option. See the document of Kernel.spawn.
IO.popen(["ls", "/", :err=>[:child, :out]]) {|ls_io|
ls_result_with_error = ls_io.read
}
# spawn options can be mixed with IO options
IO.popen(["ls", "/"], :err=>[:child, :out]) {|ls_io|
ls_result_with_error = ls_io.read
}
Raises exceptions which IO.pipe and Kernel.spawn raise.
If a block is given, Ruby will run the command as a child connected to Ruby with a pipe. Ruby’s end of the pipe will be passed as a parameter to the block. At the end of block, Ruby closes the pipe and sets $?
. In this case IO.popen returns the value of the block.
If a block is given with a cmd of “-
”, the block will be run in two separate processes: once in the parent, and once in a child. The parent process will be passed the pipe object as a parameter to the block, the child version of the block will be passed nil
, and the child’s standard in and standard out will be connected to the parent through the pipe. Not available on all platforms.
f = IO.popen("uname")
p f.readlines
f.close
puts "Parent is #{Process.pid}"
IO.popen("date") {|f| puts f.gets }
IO.popen("-") {|f| $stderr.puts "#{Process.pid} is here, f is #{f.inspect}"}
p $?
IO.popen(%w"sed -e s|^|<foo>| -e s&$&;zot;&", "r+") {|f|
f.puts "bar"; f.close_write; puts f.gets
}
produces:
["Linux\n"]
Parent is 21346
Thu Jan 15 22:41:19 JST 2009
21346 is here, f is #<IO:fd 3>
21352 is here, f is nil
#<Process::Status: pid 21352 exit 0>
<foo>bar;zot;
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# File 'io.c', line 7005
static VALUE
rb_io_s_popen(int argc, VALUE *argv, VALUE klass)
{
VALUE pname, pmode = Qnil, opt = Qnil, env = Qnil;
if (argc > 1 && !NIL_P(opt = rb_check_hash_type(argv[argc-1]))) --argc;
if (argc > 1 && !NIL_P(env = rb_check_hash_type(argv[0]))) --argc, ++argv;
switch (argc) {
case 2:
pmode = argv[1];
case 1:
pname = argv[0];
break;
default:
{
int ex = !NIL_P(opt);
rb_error_arity(argc + ex, 1 + ex, 2 + ex);
}
}
return popen_finish(rb_io_popen(pname, pmode, env, opt), klass);
}
|
.read(name, [length [, offset]][, opt]) ⇒ String
Opens the file, optionally seeks to the given offset
, then returns length
bytes (defaulting to the rest of the file). #read ensures the file is closed before returning.
If name
starts with a pipe character ("|"
), a subprocess is created in the same way as Kernel#open, and its output is returned.
Options
The options hash accepts the following keys:
- :encoding
-
string or encoding
Specifies the encoding of the read string.
:encoding
will be ignored iflength
is specified. See Encoding.aliases for possible encodings. - :mode
-
string or integer
Specifies the mode argument for open(). It must start with an “r”, otherwise it will cause an error. See IO.new for the list of possible modes.
- :open_args
-
array
Specifies arguments for open() as an array. This key can not be used in combination with either
:encoding
or:mode
.
Examples:
IO.read("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n"
IO.read("testfile", 20) #=> "This is line one\nThi"
IO.read("testfile", 20, 10) #=> "ne one\nThis is line "
IO.read("binfile", mode: "rb") #=> "\xF7\x00\x00\x0E\x12"
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# File 'io.c', line 10753
static VALUE
rb_io_s_read(int argc, VALUE *argv, VALUE io)
{
VALUE opt, offset;
struct foreach_arg arg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, &offset, NULL, &opt);
open_key_args(io, argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
if (!NIL_P(offset)) {
struct seek_arg sarg;
int state = 0;
sarg.io = arg.io;
sarg.offset = offset;
sarg.mode = SEEK_SET;
rb_protect(seek_before_access, (VALUE)&sarg, &state);
if (state) {
rb_io_close(arg.io);
rb_jump_tag(state);
}
if (arg.argc == 2) arg.argc = 1;
}
return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}
|
.readlines(name, sep = $/[, getline_args, open_args]) ⇒ Array .readlines(name, limit[, getline_args, open_args]) ⇒ Array .readlines(name, sep, limit[, getline_args, open_args]) ⇒ Array
Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep.
a = IO.readlines("testfile")
a[0] #=> "This is line one\n"
b = IO.readlines("testfile", chomp: true)
b[0] #=> "This is line one"
If the last argument is a hash, it’s the keyword argument to open.
Options for getline
The options hash accepts the following keys:
- :chomp
-
When the optional
chomp
keyword argument has a true value,\n
,\r
, and\r\n
will be removed from the end of each line.
See also IO.read for details about open_args.
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# File 'io.c', line 10674
static VALUE
rb_io_s_readlines(int argc, VALUE *argv, VALUE io)
{
VALUE opt;
struct foreach_arg arg;
struct getline_arg garg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
extract_getline_args(argc-1, argv+1, &garg);
open_key_args(io, argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
extract_getline_opts(opt, &garg);
check_getline_args(&garg.rs, &garg.limit, garg.io = arg.io);
return rb_ensure(io_s_readlines, (VALUE)&garg, rb_io_close, arg.io);
}
|
.select(read_array[, write_array [, error_array [, timeout]]]) ⇒ Array?
Calls select(2) system call. It monitors given arrays of IO objects, waits until one or more of IO objects are ready for reading, are ready for writing, and have pending exceptions respectively, and returns an array that contains arrays of those IO objects. It will return nil
if optional timeout value is given and no IO object is ready in timeout seconds.
IO.select peeks the buffer of IO objects for testing readability. If the IO buffer is not empty, IO.select immediately notifies readability. This “peek” only happens for IO objects. It does not happen for IO-like objects such as OpenSSL::SSL::SSLSocket.
The best way to use IO.select is invoking it after nonblocking methods such as #read_nonblock, #write_nonblock, etc. The methods raise an exception which is extended by IO::WaitReadable or IO::WaitWritable. The modules notify how the caller should wait with IO.select. If IO::WaitReadable is raised, the caller should wait for reading. If IO::WaitWritable is raised, the caller should wait for writing.
So, blocking read (#readpartial) can be emulated using #read_nonblock and IO.select as follows:
begin
result = io_like.read_nonblock(maxlen)
rescue IO::WaitReadable
IO.select([io_like])
retry
rescue IO::WaitWritable
IO.select(nil, [io_like])
retry
end
Especially, the combination of nonblocking methods and IO.select is preferred for IO like objects such as OpenSSL::SSL::SSLSocket. It has #to_io method to return underlying IO object. IO.select calls #to_io to obtain the file descriptor to wait.
This means that readability notified by IO.select doesn’t mean readability from OpenSSL::SSL::SSLSocket object.
The most likely situation is that OpenSSL::SSL::SSLSocket buffers some data. IO.select doesn’t see the buffer. So IO.select can block when OpenSSL::SSL::SSLSocket#readpartial doesn’t block.
However, several more complicated situations exist.
SSL is a protocol which is sequence of records. The record consists of multiple bytes. So, the remote side of SSL sends a partial record, IO.select notifies readability but OpenSSL::SSL::SSLSocket cannot decrypt a byte and OpenSSL::SSL::SSLSocket#readpartial will block.
Also, the remote side can request SSL renegotiation which forces the local SSL engine to write some data. This means OpenSSL::SSL::SSLSocket#readpartial may invoke #write system call and it can block. In such a situation, OpenSSL::SSL::SSLSocket#read_nonblock raises IO::WaitWritable instead of blocking. So, the caller should wait for ready for writability as above example.
The combination of nonblocking methods and IO.select is also useful for streams such as tty, pipe socket socket when multiple processes read from a stream.
Finally, Linux kernel developers don’t guarantee that readability of select(2) means readability of following read(2) even for a single process. See select(2) manual on GNU/Linux system.
Invoking IO.select before IO#readpartial works well as usual. However it is not the best way to use IO.select.
The writability notified by select(2) doesn’t show how many bytes are writable. IO#write method blocks until given whole string is written. So, IO#write(two or more bytes)
can block after writability is notified by IO.select. IO#write_nonblock is required to avoid the blocking.
Blocking write (#write) can be emulated using #write_nonblock and IO.select as follows: IO::WaitReadable should also be rescued for SSL renegotiation in OpenSSL::SSL::SSLSocket.
while 0 < string.bytesize
begin
written = io_like.write_nonblock(string)
rescue IO::WaitReadable
IO.select([io_like])
retry
rescue IO::WaitWritable
IO.select(nil, [io_like])
retry
end
string = string.byteslice(written..-1)
end
Parameters
- read_array
-
an array of IO objects that wait until ready for read
- write_array
-
an array of IO objects that wait until ready for write
- error_array
-
an array of IO objects that wait for exceptions
- timeout
-
a numeric value in second
Example
rp, wp = IO.pipe
mesg = "ping "
100.times {
# IO.select follows IO#read. Not the best way to use IO.select.
rs, ws, = IO.select([rp], [wp])
if r = rs[0]
ret = r.read(5)
print ret
case ret
when /ping/
mesg = "pong\n"
when /pong/
mesg = "ping "
end
end
if w = ws[0]
w.write(mesg)
end
}
produces:
ping pong
ping pong
ping pong
(snipped)
ping
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# File 'io.c', line 9736
static VALUE
rb_f_select(int argc, VALUE *argv, VALUE obj)
{
VALUE timeout;
struct select_args args;
struct timeval timerec;
int i;
rb_scan_args(argc, argv, "13", &args.read, &args.write, &args.except, &timeout);
if (NIL_P(timeout)) {
args.timeout = 0;
}
else {
timerec = rb_time_interval(timeout);
args.timeout = &timerec;
}
for (i = 0; i < numberof(args.fdsets); ++i)
rb_fd_init(&args.fdsets[i]);
return rb_ensure(select_call, (VALUE)&args, select_end, (VALUE)&args);
}
|
.sysopen(path, [mode, [perm]]) ⇒ Integer
Opens the given path, returning the underlying file descriptor as a Integer.
IO.sysopen("testfile") #=> 3
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# File 'io.c', line 7179
static VALUE
rb_io_s_sysopen(int argc, VALUE *argv, VALUE _)
{
VALUE fname, vmode, vperm;
VALUE intmode;
int oflags, fd;
mode_t perm;
rb_scan_args(argc, argv, "12", &fname, &vmode, &vperm);
FilePathValue(fname);
if (NIL_P(vmode))
oflags = O_RDONLY;
else if (!NIL_P(intmode = rb_check_to_integer(vmode, "to_int")))
oflags = NUM2INT(intmode);
else {
SafeStringValue(vmode);
oflags = rb_io_modestr_oflags(StringValueCStr(vmode));
}
if (NIL_P(vperm)) perm = 0666;
else perm = NUM2MODET(vperm);
RB_GC_GUARD(fname) = rb_str_new4(fname);
fd = rb_sysopen(fname, oflags, perm);
return INT2NUM(fd);
}
|
.try_convert(obj) ⇒ IO?
Try to convert obj into an IO, using to_io method. Returns converted IO or nil
if obj cannot be converted for any reason.
IO.try_convert(STDOUT) #=> STDOUT
IO.try_convert("STDOUT") #=> nil
require 'zlib'
f = open("/tmp/zz.gz") #=> #<File:/tmp/zz.gz>
z = Zlib::GzipReader.open(f) #=> #<Zlib::GzipReader:0x81d8744>
IO.try_convert(z) #=> #<File:/tmp/zz.gz>
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# File 'io.c', line 845
static VALUE
rb_io_s_try_convert(VALUE dummy, VALUE io)
{
return rb_io_check_io(io);
}
|
.write(name, string[, offset]) ⇒ Integer .write(name, string[, offset][, opt]) ⇒ Integer
Opens the file, optionally seeks to the given offset, writes string, then returns the length written. #write ensures the file is closed before returning. If offset is not given in write mode, the file is truncated. Otherwise, it is not truncated.
IO.write("testfile", "0123456789", 20) #=> 10
# File could contain: "This is line one\nThi0123456789two\nThis is line three\nAnd so on...\n"
IO.write("testfile", "0123456789") #=> 10
# File would now read: "0123456789"
If the last argument is a hash, it specifies options for the internal open(). It accepts the following keys:
- :encoding
-
string or encoding
Specifies the encoding of the read string. See Encoding.aliases for possible encodings.
- :mode
-
string or integer
Specifies the mode argument for open(). It must start with “w”, “a”, or “r+”, otherwise it will cause an error. See IO.new for the list of possible modes.
- :perm
-
integer
Specifies the perm argument for open().
- :open_args
-
array
Specifies arguments for open() as an array. This key can not be used in combination with other keys.
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# File 'io.c', line 10926
static VALUE
rb_io_s_write(int argc, VALUE *argv, VALUE io)
{
return io_s_write(argc, argv, io, 0);
}
|
Instance Method Details
#<<(obj) ⇒ IO
String Output—Writes obj to ios. obj will be converted to a string using to_s
.
$stdout << "Hello " << "world!\n"
produces:
Hello world!
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# File 'io.c', line 1985
VALUE
rb_io_addstr(VALUE io, VALUE str)
{
rb_io_write(io, str);
return io;
}
|
#advise(advice, offset = 0, len = 0) ⇒ nil
Announce an intention to access data from the current file in a specific pattern. On platforms that do not support the posix_fadvise(2) system call, this method is a no-op.
advice is one of the following symbols:
- :normal
-
No advice to give; the default assumption for an open file.
- :sequential
-
The data will be accessed sequentially with lower offsets read before higher ones.
- :random
-
The data will be accessed in random order.
- :willneed
-
The data will be accessed in the near future.
- :dontneed
-
The data will not be accessed in the near future.
- :noreuse
-
The data will only be accessed once.
The semantics of a piece of advice are platform-dependent. See man 2 posix_fadvise for details.
“data” means the region of the current file that begins at offset and extends for len bytes. If len is 0, the region ends at the last byte of the file. By default, both offset and len are 0, meaning that the advice applies to the entire file.
If an error occurs, one of the following exceptions will be raised:
- IOError
-
The IO stream is closed.
- Errno::EBADF
-
The file descriptor of the current file is invalid.
- Errno::EINVAL
-
An invalid value for advice was given.
- Errno::ESPIPE
-
The file descriptor of the current file refers to a FIFO or pipe. (Linux raises Errno::EINVAL in this case).
- TypeError
-
Either advice was not a Symbol, or one of the other arguments was not an Integer.
- RangeError
-
One of the arguments given was too big/small.
- This list is not exhaustive; other Errno
-
exceptions are also possible.
9572 9573 9574 9575 9576 9577 9578 9579 9580 9581 9582 9583 9584 9585 9586 9587 9588 9589 9590 9591 9592 9593 9594 |
# File 'io.c', line 9572
static VALUE
rb_io_advise(int argc, VALUE *argv, VALUE io)
{
VALUE advice, offset, len;
off_t off, l;
rb_io_t *fptr;
rb_scan_args(argc, argv, "12", &advice, &offset, &len);
advice_arg_check(advice);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
off = NIL_P(offset) ? 0 : NUM2OFFT(offset);
l = NIL_P(len) ? 0 : NUM2OFFT(len);
#ifdef HAVE_POSIX_FADVISE
return do_io_advise(fptr, advice, off, l);
#else
((void)off, (void)l); /* Ignore all hint */
return Qnil;
#endif
}
|
#autoclose=(bool) ⇒ Boolean
8640 8641 8642 8643 8644 8645 8646 8647 8648 8649 8650 |
# File 'io.c', line 8640
static VALUE
rb_io_set_autoclose(VALUE io, VALUE autoclose)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!RTEST(autoclose))
fptr->mode |= FMODE_PREP;
else
fptr->mode &= ~FMODE_PREP;
return autoclose;
}
|
#autoclose? ⇒ Boolean
Returns true
if the underlying file descriptor of ios will be closed automatically at its finalization, otherwise false
.
8615 8616 8617 8618 8619 8620 8621 |
# File 'io.c', line 8615
static VALUE
rb_io_autoclose_p(VALUE io)
{
rb_io_t *fptr = RFILE(io)->fptr;
rb_io_check_closed(fptr);
return (fptr->mode & FMODE_PREP) ? Qfalse : Qtrue;
}
|
#binmode ⇒ IO
Puts ios into binary mode. Once a stream is in binary mode, it cannot be reset to nonbinary mode.
-
newline conversion disabled
-
encoding conversion disabled
-
content is treated as ASCII-8BIT
5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515 5516 |
# File 'io.c', line 5505
static VALUE
rb_io_binmode_m(VALUE io)
{
VALUE write_io;
rb_io_ascii8bit_binmode(io);
write_io = GetWriteIO(io);
if (write_io != io)
rb_io_ascii8bit_binmode(write_io);
return io;
}
|
#binmode? ⇒ Boolean
Returns true
if ios is binmode.
5524 5525 5526 5527 5528 5529 5530 |
# File 'io.c', line 5524
static VALUE
rb_io_binmode_p(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
return fptr->mode & FMODE_BINMODE ? Qtrue : Qfalse;
}
|
#close ⇒ nil
Closes ios and flushes any pending writes to the operating system. The stream is unavailable for any further data operations; an IOError is raised if such an attempt is made. I/O streams are automatically closed when they are claimed by the garbage collector.
If ios is opened by IO.popen, #close sets $?
.
Calling this method on closed IO object is just ignored since Ruby 2.3.
4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 |
# File 'io.c', line 4945
static VALUE
rb_io_close_m(VALUE io)
{
rb_io_t *fptr = rb_io_get_fptr(io);
if (fptr->fd < 0) {
return Qnil;
}
rb_io_close(io);
return Qnil;
}
|
#close_on_exec=(bool) ⇒ Boolean
Sets a close-on-exec flag.
f = open("/dev/null")
f.close_on_exec = true
system("cat", "/proc/self/fd/#{f.fileno}") # cat: /proc/self/fd/3: No such file or directory
f.closed? #=> false
Ruby sets close-on-exec flags of all file descriptors by default since Ruby 2.0.0. So you don’t need to set by yourself. Also, unsetting a close-on-exec flag can cause file descriptor leak if another thread use fork() and exec() (via system() method for example). If you really needs file descriptor inheritance to child process, use spawn()‘s argument such as fd=>fd.
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# File 'io.c', line 4549
static VALUE
rb_io_set_close_on_exec(VALUE io, VALUE arg)
{
int flag = RTEST(arg) ? FD_CLOEXEC : 0;
rb_io_t *fptr;
VALUE write_io;
int fd, ret;
write_io = GetWriteIO(io);
if (io != write_io) {
GetOpenFile(write_io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fptr->fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret != 0) rb_sys_fail_path(fptr->pathv);
}
}
}
GetOpenFile(io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret != 0) rb_sys_fail_path(fptr->pathv);
}
}
return Qnil;
}
|
#close_on_exec? ⇒ Boolean
Returns true
if ios will be closed on exec.
f = open("/dev/null")
f.close_on_exec? #=> false
f.close_on_exec = true
f.close_on_exec? #=> true
f.close_on_exec = false
f.close_on_exec? #=> false
4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 |
# File 'io.c', line 4501
static VALUE
rb_io_close_on_exec_p(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
int fd, ret;
write_io = GetWriteIO(io);
if (io != write_io) {
GetOpenFile(write_io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if (!(ret & FD_CLOEXEC)) return Qfalse;
}
}
GetOpenFile(io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if (!(ret & FD_CLOEXEC)) return Qfalse;
}
return Qtrue;
}
|
#close_read ⇒ nil
Closes the read end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe). Will raise an IOError if the stream is not duplexed.
f = IO.popen("/bin/sh","r+")
f.close_read
f.readlines
produces:
prog.rb:3:in `readlines': not opened for reading (IOError)
from prog.rb:3
Calling this method on closed IO object is just ignored since Ruby 2.3.
5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 |
# File 'io.c', line 5044
static VALUE
rb_io_close_read(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
fptr = rb_io_get_fptr(rb_io_taint_check(io));
if (fptr->fd < 0) return Qnil;
if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_RD
# define SHUT_RD 0
#endif
if (shutdown(fptr->fd, SHUT_RD) < 0)
rb_sys_fail_path(fptr->pathv);
fptr->mode &= ~FMODE_READABLE;
if (!(fptr->mode & FMODE_WRITABLE))
return rb_io_close(io);
return Qnil;
}
write_io = GetWriteIO(io);
if (io != write_io) {
rb_io_t *wfptr;
wfptr = rb_io_get_fptr(rb_io_taint_check(write_io));
wfptr->pid = fptr->pid;
fptr->pid = 0;
RFILE(io)->fptr = wfptr;
/* bind to write_io temporarily to get rid of memory/fd leak */
fptr->tied_io_for_writing = 0;
RFILE(write_io)->fptr = fptr;
rb_io_fptr_cleanup(fptr, FALSE);
/* should not finalize fptr because another thread may be reading it */
return Qnil;
}
if ((fptr->mode & (FMODE_DUPLEX|FMODE_WRITABLE)) == FMODE_WRITABLE) {
rb_raise(rb_eIOError, "closing non-duplex IO for reading");
}
return rb_io_close(io);
}
|
#close_write ⇒ nil
Closes the write end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe). Will raise an IOError if the stream is not duplexed.
f = IO.popen("/bin/sh","r+")
f.close_write
f.print "nowhere"
produces:
prog.rb:3:in `write': not opened for writing (IOError)
from prog.rb:3:in `print'
from prog.rb:3
Calling this method on closed IO object is just ignored since Ruby 2.3.
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# File 'io.c', line 5106
static VALUE
rb_io_close_write(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
write_io = GetWriteIO(io);
fptr = rb_io_get_fptr(rb_io_taint_check(write_io));
if (fptr->fd < 0) return Qnil;
if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_WR
# define SHUT_WR 1
#endif
if (shutdown(fptr->fd, SHUT_WR) < 0)
rb_sys_fail_path(fptr->pathv);
fptr->mode &= ~FMODE_WRITABLE;
if (!(fptr->mode & FMODE_READABLE))
return rb_io_close(write_io);
return Qnil;
}
if ((fptr->mode & (FMODE_DUPLEX|FMODE_READABLE)) == FMODE_READABLE) {
rb_raise(rb_eIOError, "closing non-duplex IO for writing");
}
if (io != write_io) {
fptr = rb_io_get_fptr(rb_io_taint_check(io));
fptr->tied_io_for_writing = 0;
}
rb_io_close(write_io);
return Qnil;
}
|
#closed? ⇒ Boolean
5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 |
# File 'io.c', line 5005
static VALUE
rb_io_closed(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
rb_io_t *write_fptr;
write_io = GetWriteIO(io);
if (io != write_io) {
write_fptr = RFILE(write_io)->fptr;
if (write_fptr && 0 <= write_fptr->fd) {
return Qfalse;
}
}
fptr = rb_io_get_fptr(io);
return 0 <= fptr->fd ? Qfalse : Qtrue;
}
|
#each(sep = $/[, getline_args]) {|line| ... } ⇒ IO #each(limit[, getline_args]) {|line| ... } ⇒ IO #each(sep, limit[, getline_args]) {|line| ... } ⇒ IO #each(...) ⇒ Object
ios.each_line(sep=$/ [, getline_args]) {|line| block } -> ios
ios.each_line(limit [, getline_args]) {|line| block } -> ios
ios.each_line(sep, limit [, getline_args]) {|line| block } -> ios
ios.each_line(...) -> an_enumerator
Executes the block for every line in ios, where lines are separated by sep. ios must be opened for reading or an IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile")
f.each {|line| puts "#{f.lineno}: #{line}" }
produces:
1: This is line one
2: This is line two
3: This is line three
4: And so on...
See IO.readlines for details about getline_args.
3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 |
# File 'io.c', line 3945
static VALUE
rb_io_each_line(int argc, VALUE *argv, VALUE io)
{
VALUE str;
struct getline_arg args;
RETURN_ENUMERATOR(io, argc, argv);
prepare_getline_args(argc, argv, &args, io);
if (args.limit == 0)
rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
while (!NIL_P(str = rb_io_getline_1(args.rs, args.limit, args.chomp, io))) {
rb_yield(str);
}
return io;
}
|
#each_byte {|byte| ... } ⇒ IO #each_byte ⇒ Object
Calls the given block once for each byte (0..255) in ios, passing the byte as an argument. The stream must be opened for reading or an IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile")
checksum = 0
f.each_byte {|x| checksum ^= x } #=> #<File:testfile>
checksum #=> 12
3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 |
# File 'io.c', line 3978
static VALUE
rb_io_each_byte(VALUE io)
{
rb_io_t *fptr;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
do {
while (fptr->rbuf.len > 0) {
char *p = fptr->rbuf.ptr + fptr->rbuf.off++;
fptr->rbuf.len--;
rb_yield(INT2FIX(*p & 0xff));
errno = 0;
}
rb_io_check_byte_readable(fptr);
READ_CHECK(fptr);
} while (io_fillbuf(fptr) >= 0);
return io;
}
|
#each_char {|c| ... } ⇒ IO #each_char ⇒ Object
4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 |
# File 'io.c', line 4121
static VALUE
rb_io_each_char(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
VALUE c;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
enc = io_input_encoding(fptr);
READ_CHECK(fptr);
while (!NIL_P(c = io_getc(fptr, enc))) {
rb_yield(c);
}
return io;
}
|
#each_codepoint {|c| ... } ⇒ IO #codepoints {|c| ... } ⇒ IO #each_codepoint ⇒ Object #codepoints ⇒ Object
Passes the Integer ordinal of each character in ios, passing the codepoint as an argument. The stream must be opened for reading or an IOError will be raised.
If no block is given, an enumerator is returned instead.
4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 |
# File 'io.c', line 4155
static VALUE
rb_io_each_codepoint(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
unsigned int c;
int r, n;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
READ_CHECK(fptr);
if (NEED_READCONV(fptr)) {
SET_BINARY_MODE(fptr);
r = 1; /* no invalid char yet */
for (;;) {
make_readconv(fptr, 0);
for (;;) {
if (fptr->cbuf.len) {
if (fptr->encs.enc)
r = rb_enc_precise_mbclen(fptr->cbuf.ptr+fptr->cbuf.off,
fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
fptr->encs.enc);
else
r = ONIGENC_CONSTRUCT_MBCLEN_CHARFOUND(1);
if (!MBCLEN_NEEDMORE_P(r))
break;
if (fptr->cbuf.len == fptr->cbuf.capa) {
rb_raise(rb_eIOError, "too long character");
}
}
if (more_char(fptr) == MORE_CHAR_FINISHED) {
clear_readconv(fptr);
if (!MBCLEN_CHARFOUND_P(r)) {
enc = fptr->encs.enc;
goto invalid;
}
return io;
}
}
if (MBCLEN_INVALID_P(r)) {
enc = fptr->encs.enc;
goto invalid;
}
n = MBCLEN_CHARFOUND_LEN(r);
if (fptr->encs.enc) {
c = rb_enc_codepoint(fptr->cbuf.ptr+fptr->cbuf.off,
fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
fptr->encs.enc);
}
else {
c = (unsigned char)fptr->cbuf.ptr[fptr->cbuf.off];
}
fptr->cbuf.off += n;
fptr->cbuf.len -= n;
rb_yield(UINT2NUM(c));
}
}
NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
enc = io_input_encoding(fptr);
while (io_fillbuf(fptr) >= 0) {
r = rb_enc_precise_mbclen(fptr->rbuf.ptr+fptr->rbuf.off,
fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
if (MBCLEN_CHARFOUND_P(r) &&
(n = MBCLEN_CHARFOUND_LEN(r)) <= fptr->rbuf.len) {
c = rb_enc_codepoint(fptr->rbuf.ptr+fptr->rbuf.off,
fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
fptr->rbuf.off += n;
fptr->rbuf.len -= n;
rb_yield(UINT2NUM(c));
}
else if (MBCLEN_INVALID_P(r)) {
goto invalid;
}
else if (MBCLEN_NEEDMORE_P(r)) {
char cbuf[8], *p = cbuf;
int more = MBCLEN_NEEDMORE_LEN(r);
if (more > numberof(cbuf)) goto invalid;
more += n = fptr->rbuf.len;
if (more > numberof(cbuf)) goto invalid;
while ((n = (int)read_buffered_data(p, more, fptr)) > 0 &&
(p += n, (more -= n) > 0)) {
if (io_fillbuf(fptr) < 0) goto invalid;
if ((n = fptr->rbuf.len) > more) n = more;
}
r = rb_enc_precise_mbclen(cbuf, p, enc);
if (!MBCLEN_CHARFOUND_P(r)) goto invalid;
c = rb_enc_codepoint(cbuf, p, enc);
rb_yield(UINT2NUM(c));
}
else {
continue;
}
}
return io;
invalid:
rb_raise(rb_eArgError, "invalid byte sequence in %s", rb_enc_name(enc));
UNREACHABLE_RETURN(Qundef);
}
|
#each(sep = $/[, getline_args]) {|line| ... } ⇒ IO #each(limit[, getline_args]) {|line| ... } ⇒ IO #each(sep, limit[, getline_args]) {|line| ... } ⇒ IO #each(...) ⇒ Object
ios.each_line(sep=$/ [, getline_args]) {|line| block } -> ios
ios.each_line(limit [, getline_args]) {|line| block } -> ios
ios.each_line(sep, limit [, getline_args]) {|line| block } -> ios
ios.each_line(...) -> an_enumerator
Executes the block for every line in ios, where lines are separated by sep. ios must be opened for reading or an IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile")
f.each {|line| puts "#{f.lineno}: #{line}" }
produces:
1: This is line one
2: This is line two
3: This is line three
4: And so on...
See IO.readlines for details about getline_args.
3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 |
# File 'io.c', line 3945
static VALUE
rb_io_each_line(int argc, VALUE *argv, VALUE io)
{
VALUE str;
struct getline_arg args;
RETURN_ENUMERATOR(io, argc, argv);
prepare_getline_args(argc, argv, &args, io);
if (args.limit == 0)
rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
while (!NIL_P(str = rb_io_getline_1(args.rs, args.limit, args.chomp, io))) {
rb_yield(str);
}
return io;
}
|
#eof ⇒ Boolean #eof? ⇒ Boolean
Returns true if ios is at end of file that means there are no more data to read. The stream must be opened for reading or an IOError will be raised.
f = File.new("testfile")
dummy = f.readlines
f.eof #=> true
If ios is a stream such as pipe or socket, IO#eof? blocks until the other end sends some data or closes it.
r, w = IO.pipe
Thread.new { sleep 1; w.close }
r.eof? #=> true after 1 second blocking
r, w = IO.pipe
Thread.new { sleep 1; w.puts "a" }
r.eof? #=> false after 1 second blocking
r, w = IO.pipe
r.eof? # blocks forever
Note that IO#eof? reads data to the input byte buffer. So IO#sysread may not behave as you intend with IO#eof?, unless you call IO#rewind first (which is not available for some streams).
2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 |
# File 'io.c', line 2291
VALUE
rb_io_eof(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (READ_CHAR_PENDING(fptr)) return Qfalse;
if (READ_DATA_PENDING(fptr)) return Qfalse;
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
return eof(fptr->fd) ? Qtrue : Qfalse;
}
#endif
if (io_fillbuf(fptr) < 0) {
return Qtrue;
}
return Qfalse;
}
|
#eof ⇒ Boolean #eof? ⇒ Boolean
Returns true if ios is at end of file that means there are no more data to read. The stream must be opened for reading or an IOError will be raised.
f = File.new("testfile")
dummy = f.readlines
f.eof #=> true
If ios is a stream such as pipe or socket, IO#eof? blocks until the other end sends some data or closes it.
r, w = IO.pipe
Thread.new { sleep 1; w.close }
r.eof? #=> true after 1 second blocking
r, w = IO.pipe
Thread.new { sleep 1; w.puts "a" }
r.eof? #=> false after 1 second blocking
r, w = IO.pipe
r.eof? # blocks forever
Note that IO#eof? reads data to the input byte buffer. So IO#sysread may not behave as you intend with IO#eof?, unless you call IO#rewind first (which is not available for some streams).
2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 |
# File 'io.c', line 2291
VALUE
rb_io_eof(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (READ_CHAR_PENDING(fptr)) return Qfalse;
if (READ_DATA_PENDING(fptr)) return Qfalse;
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
return eof(fptr->fd) ? Qtrue : Qfalse;
}
#endif
if (io_fillbuf(fptr) < 0) {
return Qtrue;
}
return Qfalse;
}
|
#external_encoding ⇒ Encoding
Returns the Encoding object that represents the encoding of the file. If io is in write mode and no encoding is specified, returns nil
.
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# File 'io.c', line 11912
static VALUE
rb_io_external_encoding(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (fptr->encs.enc2) {
return rb_enc_from_encoding(fptr->encs.enc2);
}
if (fptr->mode & FMODE_WRITABLE) {
if (fptr->encs.enc)
return rb_enc_from_encoding(fptr->encs.enc);
return Qnil;
}
return rb_enc_from_encoding(io_read_encoding(fptr));
}
|
#fcntl(integer_cmd, arg) ⇒ Integer
Provides a mechanism for issuing low-level commands to control or query file-oriented I/O streams. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes (Array#pack might be a useful way to build this string). On Unix platforms, see fcntl(2)
for details. Not implemented on all platforms.
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# File 'io.c', line 10158
static VALUE
rb_io_fcntl(int argc, VALUE *argv, VALUE io)
{
VALUE req, arg;
rb_scan_args(argc, argv, "11", &req, &arg);
return rb_fcntl(io, req, arg);
}
|
#fdatasync ⇒ 0?
Immediately writes all buffered data in ios to disk.
If the underlying operating system does not support fdatasync(2), IO#fsync is called instead (which might raise a NotImplementedError).
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# File 'io.c', line 2429
static VALUE
rb_io_fdatasync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (io_fflush(fptr) < 0)
rb_sys_fail_on_write(fptr);
if ((int)rb_thread_io_blocking_region(nogvl_fdatasync, fptr, fptr->fd) == 0)
return INT2FIX(0);
/* fall back */
return rb_io_fsync(io);
}
|
#fileno ⇒ Integer #to_i ⇒ Integer Also known as: to_i
Returns an integer representing the numeric file descriptor for ios.
$stdin.fileno #=> 0
$stdout.fileno #=> 1
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# File 'io.c', line 2462
static VALUE
rb_io_fileno(VALUE io)
{
rb_io_t *fptr = RFILE(io)->fptr;
int fd;
rb_io_check_closed(fptr);
fd = fptr->fd;
return INT2FIX(fd);
}
|
#flush ⇒ IO
Flushes any buffered data within ios to the underlying operating system (note that this is Ruby internal buffering only; the OS may buffer the data as well).
$stdout.print "no newline"
$stdout.flush
produces:
no newline
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# File 'io.c', line 2045
VALUE
rb_io_flush(VALUE io)
{
return rb_io_flush_raw(io, 1);
}
|
#fsync ⇒ 0?
Immediately writes all buffered data in ios to disk. Note that #fsync differs from using IO#sync=. The latter ensures that data is flushed from Ruby’s buffers, but does not guarantee that the underlying operating system actually writes it to disk.
NotImplementedError is raised if the underlying operating system does not support fsync(2).
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# File 'io.c', line 2380
static VALUE
rb_io_fsync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (io_fflush(fptr) < 0)
rb_sys_fail_on_write(fptr);
if ((int)rb_thread_io_blocking_region(nogvl_fsync, fptr, fptr->fd) < 0)
rb_sys_fail_path(fptr->pathv);
return INT2FIX(0);
}
|
#getbyte ⇒ Integer?
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# File 'io.c', line 4318
VALUE
rb_io_getbyte(VALUE io)
{
rb_io_t *fptr;
int c;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
READ_CHECK(fptr);
VALUE r_stdout = rb_ractor_stdout();
if (fptr->fd == 0 && (fptr->mode & FMODE_TTY) && RB_TYPE_P(r_stdout, T_FILE)) {
rb_io_t *ofp;
GetOpenFile(r_stdout, ofp);
if (ofp->mode & FMODE_TTY) {
rb_io_flush(r_stdout);
}
}
if (io_fillbuf(fptr) < 0) {
return Qnil;
}
fptr->rbuf.off++;
fptr->rbuf.len--;
c = (unsigned char)fptr->rbuf.ptr[fptr->rbuf.off-1];
return INT2FIX(c & 0xff);
}
|
#getc ⇒ String?
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# File 'io.c', line 4269
static VALUE
rb_io_getc(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
enc = io_input_encoding(fptr);
READ_CHECK(fptr);
return io_getc(fptr, enc);
}
|
#gets(sep = $/[, getline_args]) ⇒ String? #gets(limit[, getline_args]) ⇒ String? #gets(sep, limit[, getline_args]) ⇒ String?
Reads the next “line” from the I/O stream; lines are separated by sep. A separator of nil
reads the entire contents, and a zero-length separator reads the input a paragraph at a time (two successive newlines in the input separate paragraphs). The stream must be opened for reading or an IOError will be raised. The line read in will be returned and also assigned to $_
. Returns nil
if called at end of file. If the first argument is an integer, or optional second argument is given, the returning string would not be longer than the given value in bytes.
File.new("testfile").gets #=> "This is line one\n"
$_ #=> "This is line one\n"
File.new("testfile").gets(4)#=> "This"
If IO contains multibyte characters byte then gets(1)
returns character entirely:
# Russian characters take 2 bytes
File.write("testfile", "\u{442 435 441 442}")
File.open("testfile") {|f|f.gets(1)} #=> "\u0442"
File.open("testfile") {|f|f.gets(2)} #=> "\u0442"
File.open("testfile") {|f|f.gets(3)} #=> "\u0442\u0435"
File.open("testfile") {|f|f.gets(4)} #=> "\u0442\u0435"
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# File 'io.c', line 3774
static VALUE
rb_io_gets_m(int argc, VALUE *argv, VALUE io)
{
VALUE str;
str = rb_io_getline(argc, argv, io);
rb_lastline_set(str);
return str;
}
|
#initialize_copy(io) ⇒ Object
:nodoc:
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# File 'io.c', line 7586
static VALUE
rb_io_init_copy(VALUE dest, VALUE io)
{
rb_io_t *fptr, *orig;
int fd;
VALUE write_io;
off_t pos;
io = rb_io_get_io(io);
if (!OBJ_INIT_COPY(dest, io)) return dest;
GetOpenFile(io, orig);
MakeOpenFile(dest, fptr);
rb_io_flush(io);
/* copy rb_io_t structure */
fptr->mode = orig->mode & ~FMODE_PREP;
fptr->encs = orig->encs;
fptr->pid = orig->pid;
fptr->lineno = orig->lineno;
if (!NIL_P(orig->pathv)) fptr->pathv = orig->pathv;
fptr_copy_finalizer(fptr, orig);
fd = ruby_dup(orig->fd);
fptr->fd = fd;
pos = io_tell(orig);
if (0 <= pos)
io_seek(fptr, pos, SEEK_SET);
if (fptr->mode & FMODE_BINMODE) {
rb_io_binmode(dest);
}
write_io = GetWriteIO(io);
if (io != write_io) {
write_io = rb_obj_dup(write_io);
fptr->tied_io_for_writing = write_io;
rb_ivar_set(dest, rb_intern("@tied_io_for_writing"), write_io);
}
return dest;
}
|
#inspect ⇒ String
Return a string describing this IO object.
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# File 'io.c', line 2513
static VALUE
rb_io_inspect(VALUE obj)
{
rb_io_t *fptr;
VALUE result;
static const char closed[] = " (closed)";
fptr = RFILE(obj)->fptr;
if (!fptr) return rb_any_to_s(obj);
result = rb_str_new_cstr("#<");
rb_str_append(result, rb_class_name(CLASS_OF(obj)));
rb_str_cat2(result, ":");
if (NIL_P(fptr->pathv)) {
if (fptr->fd < 0) {
rb_str_cat(result, closed+1, strlen(closed)-1);
}
else {
rb_str_catf(result, "fd %d", fptr->fd);
}
}
else {
rb_str_append(result, fptr->pathv);
if (fptr->fd < 0) {
rb_str_cat(result, closed, strlen(closed));
}
}
return rb_str_cat2(result, ">");
}
|
#internal_encoding ⇒ Encoding
Returns the Encoding of the internal string if conversion is specified. Otherwise returns nil
.
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# File 'io.c', line 11937
static VALUE
rb_io_internal_encoding(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!fptr->encs.enc2) return Qnil;
return rb_enc_from_encoding(io_read_encoding(fptr));
}
|
#ioctl(integer_cmd, arg) ⇒ Integer
Provides a mechanism for issuing low-level commands to control or query I/O devices. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes. On Unix platforms, see ioctl(2)
for details. Not implemented on all platforms.
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# File 'io.c', line 10064
static VALUE
rb_io_ioctl(int argc, VALUE *argv, VALUE io)
{
VALUE req, arg;
rb_scan_args(argc, argv, "11", &req, &arg);
return rb_ioctl(io, req, arg);
}
|
#isatty ⇒ Boolean #tty? ⇒ Boolean
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# File 'io.c', line 4475
static VALUE
rb_io_isatty(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (isatty(fptr->fd) == 0)
return Qfalse;
return Qtrue;
}
|
#lineno ⇒ Integer
Returns the current line number in ios. The stream must be opened for reading. #lineno counts the number of times #gets is called rather than the number of newlines encountered. The two values will differ if #gets is called with a separator other than newline.
Methods that use $/
like #each, #lines and #readline will also increment #lineno.
See also the $.
variable.
f = File.new("testfile")
f.lineno #=> 0
f.gets #=> "This is line one\n"
f.lineno #=> 1
f.gets #=> "This is line two\n"
f.lineno #=> 2
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# File 'io.c', line 3807
static VALUE
rb_io_lineno(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
return INT2NUM(fptr->lineno);
}
|
#lineno=(integer) ⇒ Integer
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# File 'io.c', line 3834
static VALUE
rb_io_set_lineno(VALUE io, VALUE lineno)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
fptr->lineno = NUM2INT(lineno);
return lineno;
}
|
#pid ⇒ Integer
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# File 'io.c', line 2494
static VALUE
rb_io_pid(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!fptr->pid)
return Qnil;
return PIDT2NUM(fptr->pid);
}
|
#pos ⇒ Integer #tell ⇒ Integer
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# File 'io.c', line 2064
static VALUE
rb_io_tell(VALUE io)
{
rb_io_t *fptr;
off_t pos;
GetOpenFile(io, fptr);
pos = io_tell(fptr);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
pos -= fptr->rbuf.len;
return OFFT2NUM(pos);
}
|
#pos=(integer) ⇒ Integer
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# File 'io.c', line 2158
static VALUE
rb_io_set_pos(VALUE io, VALUE offset)
{
rb_io_t *fptr;
off_t pos;
pos = NUM2OFFT(offset);
GetOpenFile(io, fptr);
pos = io_seek(fptr, pos, SEEK_SET);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
return OFFT2NUM(pos);
}
|
#pread(maxlen, offset[, outbuf]) ⇒ String
Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset. This is advantageous compared to combining IO#seek and IO#read in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. If the optional outbuf argument is present, it must reference a String, which will receive the data. Raises SystemCallError on error, EOFError at end of file and NotImplementedError if platform does not implement the system call.
File.write("testfile", "This is line one\nThis is line two\n")
File.open("testfile") do |f|
p f.read # => "This is line one\nThis is line two\n"
p f.pread(12, 0) # => "This is line"
p f.pread(9, 8) # => "line one\n"
end
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# File 'io.c', line 5336
static VALUE
rb_io_pread(int argc, VALUE *argv, VALUE io)
{
VALUE len, offset, str;
rb_io_t *fptr;
ssize_t n;
struct prdwr_internal_arg arg;
int shrinkable;
rb_scan_args(argc, argv, "21", &len, &offset, &str);
arg.count = NUM2SIZET(len);
arg.offset = NUM2OFFT(offset);
shrinkable = io_setstrbuf(&str, (long)arg.count);
if (arg.count == 0) return str;
arg.buf = RSTRING_PTR(str);
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
arg.fd = fptr->fd;
rb_io_check_closed(fptr);
rb_str_locktmp(str);
n = (ssize_t)rb_ensure(pread_internal_call, (VALUE)&arg, rb_str_unlocktmp, str);
if (n < 0) {
rb_sys_fail_path(fptr->pathv);
}
io_set_read_length(str, n, shrinkable);
if (n == 0 && arg.count > 0) {
rb_eof_error();
}
return str;
}
|
#print ⇒ nil #print(obj, ...) ⇒ nil
Writes the given object(s) to ios. Returns nil
.
The stream must be opened for writing. Each given object that isn’t a string will be converted by calling its to_s
method. When called without arguments, prints the contents of $_
.
If the output field separator ($,
) is not nil
, it is inserted between objects. If the output record separator ($\
) is not nil
, it is appended to the output.
$stdout.print("This is ", 100, " percent.\n")
produces:
This is 100 percent.
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# File 'io.c', line 7707
VALUE
rb_io_print(int argc, const VALUE *argv, VALUE out)
{
int i;
VALUE line;
/* if no argument given, print `$_' */
if (argc == 0) {
argc = 1;
line = rb_lastline_get();
argv = &line;
}
if (argc > 1 && !NIL_P(rb_output_fs)) {
rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
}
for (i=0; i<argc; i++) {
if (!NIL_P(rb_output_fs) && i>0) {
rb_io_write(out, rb_output_fs);
}
rb_io_write(out, argv[i]);
}
if (argc > 0 && !NIL_P(rb_output_rs)) {
rb_io_write(out, rb_output_rs);
}
return Qnil;
}
|
#printf(format_string[, obj, ...]) ⇒ nil
Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.
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# File 'io.c', line 7636
VALUE
rb_io_printf(int argc, const VALUE *argv, VALUE out)
{
rb_io_write(out, rb_f_sprintf(argc, argv));
return Qnil;
}
|
#putc(obj) ⇒ Object
If obj is Numeric, write the character whose code is the least-significant byte of obj. If obj is String, write the first character of obj to ios. Otherwise, raise TypeError.
$stdout.putc "A"
$stdout.putc 65
produces:
AA
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# File 'io.c', line 7782
static VALUE
rb_io_putc(VALUE io, VALUE ch)
{
VALUE str;
if (RB_TYPE_P(ch, T_STRING)) {
str = rb_str_substr(ch, 0, 1);
}
else {
char c = NUM2CHR(ch);
str = rb_str_new(&c, 1);
}
rb_io_write(io, str);
return ch;
}
|
#puts(obj, ...) ⇒ nil
Writes the given object(s) to ios. Writes a newline after any that do not already end with a newline sequence. Returns nil
.
The stream must be opened for writing. If called with an array argument, writes each element on a new line. Each given object that isn’t a string or array will be converted by calling its to_s
method. If called without arguments, outputs a single newline.
$stdout.puts("this", "is", ["a", "test"])
produces:
this
is
a
test
Note that puts
always uses newlines and is not affected by the output record separator ($\
).
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# File 'io.c', line 7882
VALUE
rb_io_puts(int argc, const VALUE *argv, VALUE out)
{
int i, n;
VALUE line, args[2];
/* if no argument given, print newline. */
if (argc == 0) {
rb_io_write(out, rb_default_rs);
return Qnil;
}
for (i=0; i<argc; i++) {
if (RB_TYPE_P(argv[i], T_STRING)) {
line = argv[i];
goto string;
}
if (rb_exec_recursive(io_puts_ary, argv[i], out)) {
continue;
}
line = rb_obj_as_string(argv[i]);
string:
n = 0;
args[n++] = line;
if (RSTRING_LEN(line) == 0 ||
!rb_str_end_with_asciichar(line, '\n')) {
args[n++] = rb_default_rs;
}
rb_io_writev(out, n, args);
}
return Qnil;
}
|
#pwrite(string, offset) ⇒ Integer
Writes the given string to ios at offset using pwrite() system call. This is advantageous to combining IO#seek and IO#write in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. Returns the number of bytes written. Raises SystemCallError on error and NotImplementedError if platform does not implement the system call.
File.open("out", "w") do |f|
f.pwrite("ABCDEF", 3) #=> 6
end
File.read("out") #=> "\u0000\u0000\u0000ABCDEF"
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# File 'io.c', line 5404
static VALUE
rb_io_pwrite(VALUE io, VALUE str, VALUE offset)
{
rb_io_t *fptr;
ssize_t n;
struct prdwr_internal_arg arg;
VALUE tmp;
if (!RB_TYPE_P(str, T_STRING))
str = rb_obj_as_string(str);
arg.offset = NUM2OFFT(offset);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
rb_io_check_writable(fptr);
arg.fd = fptr->fd;
tmp = rb_str_tmp_frozen_acquire(str);
arg.buf = RSTRING_PTR(tmp);
arg.count = (size_t)RSTRING_LEN(tmp);
n = (ssize_t)rb_thread_io_blocking_region(internal_pwrite_func, &arg, fptr->fd);
if (n < 0) rb_sys_fail_path(fptr->pathv);
rb_str_tmp_frozen_release(str, tmp);
return SSIZET2NUM(n);
}
|
#read([length [, outbuf]]) ⇒ String?
Reads length bytes from the I/O stream.
length must be a non-negative integer or nil
.
If length is a positive integer, read
tries to read length bytes without any conversion (binary mode). It returns nil
if an EOF is encountered before anything can be read. Fewer than length bytes are returned if an EOF is encountered during the read. In the case of an integer length, the resulting string is always in ASCII-8BIT encoding.
If length is omitted or is nil
, it reads until EOF and the encoding conversion is applied, if applicable. A string is returned even if EOF is encountered before any data is read.
If length is zero, it returns an empty string (""
).
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
When this method is called at end of file, it returns nil
or ""
, depending on length: read
, read(nil)
, and read(0)
return ""
, read(positive_integer)
returns nil
.
f = File.new("testfile")
f.read(16) #=> "This is line one"
# read whole file
open("file") do |f|
data = f.read # This returns a string even if the file is empty.
# ...
end
# iterate over fixed length records
open("fixed-record-file") do |f|
while record = f.read(256)
# ...
end
end
# iterate over variable length records,
# each record is prefixed by its 32-bit length
open("variable-record-file") do |f|
while len = f.read(4)
len = len.unpack("N")[0] # 32-bit length
record = f.read(len) # This returns a string even if len is 0.
end
end
Note that this method behaves like the fread() function in C. This means it retries to invoke read(2) system calls to read data with the specified length (or until EOF). This behavior is preserved even if ios is in non-blocking mode. (This method is non-blocking flag insensitive as other methods.) If you need the behavior like a single read(2) system call, consider #readpartial, #read_nonblock, and #sysread.
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# File 'io.c', line 3260
static VALUE
io_read(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
long n, len;
VALUE length, str;
int shrinkable;
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
int previous_mode;
#endif
rb_scan_args(argc, argv, "02", &length, &str);
if (NIL_P(length)) {
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
return read_all(fptr, remain_size(fptr), str);
}
len = NUM2LONG(length);
if (len < 0) {
rb_raise(rb_eArgError, "negative length %ld given", len);
}
shrinkable = io_setstrbuf(&str,len);
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
if (len == 0) {
io_set_read_length(str, 0, shrinkable);
return str;
}
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
previous_mode = set_binary_mode_with_seek_cur(fptr);
#endif
n = io_fread(str, 0, len, fptr);
io_set_read_length(str, n, shrinkable);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (previous_mode == O_TEXT) {
setmode(fptr->fd, O_TEXT);
}
#endif
if (n == 0) return Qnil;
return str;
}
|
#readbyte ⇒ Integer
Reads a byte as with IO#getbyte, but raises an EOFError on end of file.
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# File 'io.c', line 4352
static VALUE
rb_io_readbyte(VALUE io)
{
VALUE c = rb_io_getbyte(io);
if (NIL_P(c)) {
rb_eof_error();
}
return c;
}
|
#readchar ⇒ String
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# File 'io.c', line 4295
static VALUE
rb_io_readchar(VALUE io)
{
VALUE c = rb_io_getc(io);
if (NIL_P(c)) {
rb_eof_error();
}
return c;
}
|
#readline(sep = $/[, getline_args]) ⇒ String #readline(limit[, getline_args]) ⇒ String #readline(sep, limit[, getline_args]) ⇒ String
Reads a line as with IO#gets, but raises an EOFError on end of file.
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# File 'io.c', line 3854
static VALUE
rb_io_readline(int argc, VALUE *argv, VALUE io)
{
VALUE line = rb_io_gets_m(argc, argv, io);
if (NIL_P(line)) {
rb_eof_error();
}
return line;
}
|
#readlines(sep = $/[, getline_args]) ⇒ Array #readlines(limit[, getline_args]) ⇒ Array #readlines(sep, limit[, getline_args]) ⇒ Array
Reads all of the lines in ios, and returns them in an array. Lines are separated by the optional sep. If sep is nil
, the rest of the stream is returned as a single record. If the first argument is an integer, or an optional second argument is given, the returning string would not be longer than the given value in bytes. The stream must be opened for reading or an IOError will be raised.
f = File.new("testfile")
f.readlines[0] #=> "This is line one\n"
f = File.new("testfile", chomp: true)
f.readlines[0] #=> "This is line one"
See IO.readlines for details about getline_args.
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# File 'io.c', line 3891
static VALUE
rb_io_readlines(int argc, VALUE *argv, VALUE io)
{
struct getline_arg args;
prepare_getline_args(argc, argv, &args, io);
return io_readlines(&args, io);
}
|
#readpartial(maxlen) ⇒ String #readpartial(maxlen, outbuf) ⇒ Object
Reads at most maxlen bytes from the I/O stream. It blocks only if ios has no data immediately available. It doesn’t block if some data available.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
It raises EOFError on end of file.
readpartial is designed for streams such as pipe, socket, tty, etc. It blocks only when no data immediately available. This means that it blocks only when following all conditions hold.
-
the byte buffer in the IO object is empty.
-
the content of the stream is empty.
-
the stream is not reached to EOF.
When readpartial blocks, it waits data or EOF on the stream. If some data is reached, readpartial returns with the data. If EOF is reached, readpartial raises EOFError.
When readpartial doesn’t blocks, it returns or raises immediately. If the byte buffer is not empty, it returns the data in the buffer. Otherwise if the stream has some content, it returns the data in the stream. Otherwise if the stream is reached to EOF, it raises EOFError.
r, w = IO.pipe # buffer pipe content
w << "abc" # "" "abc".
r.readpartial(4096) #=> "abc" "" ""
r.readpartial(4096) # blocks because buffer and pipe is empty.
r, w = IO.pipe # buffer pipe content
w << "abc" # "" "abc"
w.close # "" "abc" EOF
r.readpartial(4096) #=> "abc" "" EOF
r.readpartial(4096) # raises EOFError
r, w = IO.pipe # buffer pipe content
w << "abc\ndef\n" # "" "abc\ndef\n"
r.gets #=> "abc\n" "def\n" ""
w << "ghi\n" # "def\n" "ghi\n"
r.readpartial(4096) #=> "def\n" "" "ghi\n"
r.readpartial(4096) #=> "ghi\n" "" ""
Note that readpartial behaves similar to sysread. The differences are:
-
If the byte buffer is not empty, read from the byte buffer instead of “sysread for buffered IO (IOError)”.
-
It doesn’t cause Errno::EWOULDBLOCK and Errno::EINTR. When readpartial meets EWOULDBLOCK and EINTR by read system call, readpartial retry the system call.
The latter means that readpartial is nonblocking-flag insensitive. It blocks on the situation IO#sysread causes Errno::EWOULDBLOCK as if the fd is blocking mode.
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# File 'io.c', line 3084
static VALUE
io_readpartial(int argc, VALUE *argv, VALUE io)
{
VALUE ret;
ret = io_getpartial(argc, argv, io, Qnil, 0);
if (NIL_P(ret))
rb_eof_error();
return ret;
}
|
#reopen(other_IO) ⇒ IO #reopen(path, mode[, opt]) ⇒ IO
Reassociates ios with the I/O stream given in other_IO or to a new stream opened on path. This may dynamically change the actual class of this stream. The mode
and opt
parameters accept the same values as IO.open.
f1 = File.new("testfile")
f2 = File.new("testfile")
f2.readlines[0] #=> "This is line one\n"
f2.reopen(f1) #=> #<File:testfile>
f2.readlines[0] #=> "This is line one\n"
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# File 'io.c', line 7497
static VALUE
rb_io_reopen(int argc, VALUE *argv, VALUE file)
{
VALUE fname, nmode, opt;
int oflags;
rb_io_t *fptr;
if (rb_scan_args(argc, argv, "11:", &fname, &nmode, &opt) == 1) {
VALUE tmp = rb_io_check_io(fname);
if (!NIL_P(tmp)) {
return io_reopen(file, tmp);
}
}
FilePathValue(fname);
rb_io_taint_check(file);
fptr = RFILE(file)->fptr;
if (!fptr) {
fptr = RFILE(file)->fptr = ZALLOC(rb_io_t);
}
if (!NIL_P(nmode) || !NIL_P(opt)) {
int fmode;
convconfig_t convconfig;
rb_io_extract_modeenc(&nmode, 0, opt, &oflags, &fmode, &convconfig);
if (IS_PREP_STDIO(fptr) &&
((fptr->mode & FMODE_READWRITE) & (fmode & FMODE_READWRITE)) !=
(fptr->mode & FMODE_READWRITE)) {
rb_raise(rb_eArgError,
"%s can't change access mode from \"%s\" to \"%s\"",
PREP_STDIO_NAME(fptr), rb_io_fmode_modestr(fptr->mode),
rb_io_fmode_modestr(fmode));
}
fptr->mode = fmode;
fptr->encs = convconfig;
}
else {
oflags = rb_io_fmode_oflags(fptr->mode);
}
fptr->pathv = fname;
if (fptr->fd < 0) {
fptr->fd = rb_sysopen(fptr->pathv, oflags, 0666);
fptr->stdio_file = 0;
return file;
}
if (fptr->mode & FMODE_WRITABLE) {
if (io_fflush(fptr) < 0)
rb_sys_fail_on_write(fptr);
}
fptr->rbuf.off = fptr->rbuf.len = 0;
if (fptr->stdio_file) {
int e = rb_freopen(rb_str_encode_ospath(fptr->pathv),
rb_io_oflags_modestr(oflags),
fptr->stdio_file);
if (e) rb_syserr_fail_path(e, fptr->pathv);
fptr->fd = fileno(fptr->stdio_file);
rb_fd_fix_cloexec(fptr->fd);
#ifdef USE_SETVBUF
if (setvbuf(fptr->stdio_file, NULL, _IOFBF, 0) != 0)
rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
#endif
if (fptr->stdio_file == stderr) {
if (setvbuf(fptr->stdio_file, NULL, _IONBF, BUFSIZ) != 0)
rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
}
else if (fptr->stdio_file == stdout && isatty(fptr->fd)) {
if (setvbuf(fptr->stdio_file, NULL, _IOLBF, BUFSIZ) != 0)
rb_warn("setvbuf() can't be honoured for %"PRIsVALUE, fptr->pathv);
}
}
else {
int tmpfd = rb_sysopen(fptr->pathv, oflags, 0666);
int err = 0;
if (rb_cloexec_dup2(tmpfd, fptr->fd) < 0)
err = errno;
(void)close(tmpfd);
if (err) {
rb_syserr_fail_path(err, fptr->pathv);
}
}
return file;
}
|
#rewind ⇒ 0
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# File 'io.c', line 2190
static VALUE
rb_io_rewind(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (io_seek(fptr, 0L, 0) < 0 && errno) rb_sys_fail_path(fptr->pathv);
if (io == ARGF.current_file) {
ARGF.lineno -= fptr->lineno;
}
fptr->lineno = 0;
if (fptr->readconv) {
clear_readconv(fptr);
}
return INT2FIX(0);
}
|
#seek(amount, whence = IO::SEEK_SET) ⇒ 0
Seeks to a given offset anInteger in the stream according to the value of whence:
:CUR or IO::SEEK_CUR | Seeks to _amount_ plus current position
----------------------+--------------------------------------------------
:END or IO::SEEK_END | Seeks to _amount_ plus end of stream (you
| probably want a negative value for _amount_)
----------------------+--------------------------------------------------
:SET or IO::SEEK_SET | Seeks to the absolute location given by _amount_
Example:
f = File.new("testfile")
f.seek(-13, IO::SEEK_END) #=> 0
f.readline #=> "And so on...\n"
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# File 'io.c', line 2132
static VALUE
rb_io_seek_m(int argc, VALUE *argv, VALUE io)
{
VALUE offset, ptrname;
int whence = SEEK_SET;
if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
whence = interpret_seek_whence(ptrname);
}
return rb_io_seek(io, offset, whence);
}
|
#set_encoding(ext_enc) ⇒ IO #set_encoding("ext_enc: int_enc") ⇒ IO #set_encoding(ext_enc, int_enc) ⇒ IO #set_encoding("ext_enc: int_enc", opt) ⇒ IO #set_encoding(ext_enc, int_enc, opt) ⇒ IO
If single argument is specified, read string from io is tagged with the encoding specified. If encoding is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.
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# File 'io.c', line 11966
static VALUE
rb_io_set_encoding(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
VALUE v1, v2, opt;
if (!RB_TYPE_P(io, T_FILE)) {
return rb_funcallv(io, id_set_encoding, argc, argv);
}
argc = rb_scan_args(argc, argv, "11:", &v1, &v2, &opt);
GetOpenFile(io, fptr);
io_encoding_set(fptr, v1, v2, opt);
return io;
}
|
#set_encoding_by_bom ⇒ Encoding?
Checks if ios
starts with a BOM, and then consumes it and sets the external encoding. Returns the result encoding if found, or nil. If ios
is not binmode or its encoding has been set already, an exception will be raised.
File.write("bom.txt", "\u{FEFF}abc")
ios = File.open("bom.txt", "rb")
ios.set_encoding_by_bom #=> #<Encoding:UTF-8>
File.write("nobom.txt", "abc")
ios = File.open("nobom.txt", "rb")
ios.set_encoding_by_bom #=> nil
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# File 'io.c', line 8513
static VALUE
rb_io_set_encoding_by_bom(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!(fptr->mode & FMODE_BINMODE)) {
rb_raise(rb_eArgError, "ASCII incompatible encoding needs binmode");
}
if (fptr->encs.enc2) {
rb_raise(rb_eArgError, "encoding conversion is set");
}
else if (fptr->encs.enc && fptr->encs.enc != rb_ascii8bit_encoding()) {
rb_raise(rb_eArgError, "encoding is set to %s already",
rb_enc_name(fptr->encs.enc));
}
if (!io_set_encoding_by_bom(io)) return Qnil;
return rb_enc_from_encoding(fptr->encs.enc);
}
|
#stat ⇒ Object
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# File 'file.c', line 1333
static VALUE
rb_io_stat(VALUE obj)
{
rb_io_t *fptr;
struct stat st;
GetOpenFile(obj, fptr);
if (fstat(fptr->fd, &st) == -1) {
rb_sys_fail_path(fptr->pathv);
}
return rb_stat_new(&st);
}
|
#sync ⇒ Boolean
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# File 'io.c', line 2326
static VALUE
rb_io_sync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
return (fptr->mode & FMODE_SYNC) ? Qtrue : Qfalse;
}
|
#sync=(sync) ⇒ Object
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# File 'io.c', line 2397
static VALUE
rb_io_set_sync(VALUE io, VALUE sync)
{
rb_notimplement();
UNREACHABLE;
}
|
#sysread(maxlen[, outbuf]) ⇒ String
Reads maxlen bytes from ios using a low-level read and returns them as a string. Do not mix with other methods that read from ios or you may get unpredictable results.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
Raises SystemCallError on error and EOFError at end of file.
f = File.new("testfile")
f.sysread(16) #=> "This is line one"
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# File 'io.c', line 5239
static VALUE
rb_io_sysread(int argc, VALUE *argv, VALUE io)
{
VALUE len, str;
rb_io_t *fptr;
long n, ilen;
struct io_internal_read_struct iis;
int shrinkable;
rb_scan_args(argc, argv, "11", &len, &str);
ilen = NUM2LONG(len);
shrinkable = io_setstrbuf(&str, ilen);
if (ilen == 0) return str;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
if (READ_DATA_BUFFERED(fptr)) {
rb_raise(rb_eIOError, "sysread for buffered IO");
}
/*
* FIXME: removing rb_thread_wait_fd() here changes sysread semantics
* on non-blocking IOs. However, it's still currently possible
* for sysread to raise Errno::EAGAIN if another thread read()s
* the IO after we return from rb_thread_wait_fd() but before
* we call read()
*/
rb_thread_wait_fd(fptr->fd);
rb_io_check_closed(fptr);
io_setstrbuf(&str, ilen);
iis.fd = fptr->fd;
iis.nonblock = 1; /* for historical reasons, maybe (see above) */
iis.buf = RSTRING_PTR(str);
iis.capa = ilen;
n = read_internal_locktmp(str, &iis);
if (n < 0) {
rb_sys_fail_path(fptr->pathv);
}
io_set_read_length(str, n, shrinkable);
if (n == 0 && ilen > 0) {
rb_eof_error();
}
return str;
}
|
#sysseek(offset, whence = IO::SEEK_SET) ⇒ Integer
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# File 'io.c', line 5152
static VALUE
rb_io_sysseek(int argc, VALUE *argv, VALUE io)
{
VALUE offset, ptrname;
int whence = SEEK_SET;
rb_io_t *fptr;
off_t pos;
if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
whence = interpret_seek_whence(ptrname);
}
pos = NUM2OFFT(offset);
GetOpenFile(io, fptr);
if ((fptr->mode & FMODE_READABLE) &&
(READ_DATA_BUFFERED(fptr) || READ_CHAR_PENDING(fptr))) {
rb_raise(rb_eIOError, "sysseek for buffered IO");
}
if ((fptr->mode & FMODE_WRITABLE) && fptr->wbuf.len) {
rb_warn("sysseek for buffered IO");
}
errno = 0;
pos = lseek(fptr->fd, pos, whence);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
return OFFT2NUM(pos);
}
|
#syswrite(string) ⇒ Integer
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# File 'io.c', line 5192
static VALUE
rb_io_syswrite(VALUE io, VALUE str)
{
VALUE tmp;
rb_io_t *fptr;
long n, len;
const char *ptr;
if (!RB_TYPE_P(str, T_STRING))
str = rb_obj_as_string(str);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
rb_io_check_writable(fptr);
if (fptr->wbuf.len) {
rb_warn("syswrite for buffered IO");
}
tmp = rb_str_tmp_frozen_acquire(str);
RSTRING_GETMEM(tmp, ptr, len);
n = rb_write_internal(fptr->fd, ptr, len);
if (n < 0) rb_sys_fail_path(fptr->pathv);
rb_str_tmp_frozen_release(str, tmp);
return LONG2FIX(n);
}
|
#pos ⇒ Integer #tell ⇒ Integer
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# File 'io.c', line 2064
static VALUE
rb_io_tell(VALUE io)
{
rb_io_t *fptr;
off_t pos;
GetOpenFile(io, fptr);
pos = io_tell(fptr);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
pos -= fptr->rbuf.len;
return OFFT2NUM(pos);
}
|
#to_io ⇒ IO
Returns ios.
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# File 'io.c', line 2549
static VALUE
rb_io_to_io(VALUE io)
{
return io;
}
|
#isatty ⇒ Boolean #tty? ⇒ Boolean
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# File 'io.c', line 4475
static VALUE
rb_io_isatty(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (isatty(fptr->fd) == 0)
return Qfalse;
return Qtrue;
}
|
#ungetbyte(string) ⇒ nil #ungetbyte(integer) ⇒ nil
Pushes back bytes (passed as a parameter) onto ios, such that a subsequent buffered read will return it. Only one byte may be pushed back before a subsequent read operation (that is, you will be able to read only the last of several bytes that have been pushed back). Has no effect with unbuffered reads (such as IO#sysread).
f = File.new("testfile") #=> #<File:testfile>
b = f.getbyte #=> 0x38
f.ungetbyte(b) #=> nil
f.getbyte #=> 0x38
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# File 'io.c', line 4380
VALUE
rb_io_ungetbyte(VALUE io, VALUE b)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
switch (TYPE(b)) {
case T_NIL:
return Qnil;
case T_FIXNUM:
case T_BIGNUM: ;
VALUE v = rb_int_modulo(b, INT2FIX(256));
unsigned char c = NUM2INT(v) & 0xFF;
b = rb_str_new((const char *)&c, 1);
break;
default:
SafeStringValue(b);
}
io_ungetbyte(b, fptr);
return Qnil;
}
|
#ungetc(string) ⇒ nil
Pushes back one character (passed as a parameter) onto ios, such that a subsequent buffered character read will return it. Only one character may be pushed back before a subsequent read operation (that is, you will be able to read only the last of several characters that have been pushed back). Has no effect with unbuffered reads (such as IO#sysread).
f = File.new("testfile") #=> #<File:testfile>
c = f.getc #=> "8"
f.ungetc(c) #=> nil
f.getc #=> "8"
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# File 'io.c', line 4419
VALUE
rb_io_ungetc(VALUE io, VALUE c)
{
rb_io_t *fptr;
long len;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (FIXNUM_P(c)) {
c = rb_enc_uint_chr(FIX2UINT(c), io_read_encoding(fptr));
}
else if (RB_TYPE_P(c, T_BIGNUM)) {
c = rb_enc_uint_chr(NUM2UINT(c), io_read_encoding(fptr));
}
else {
SafeStringValue(c);
}
if (NEED_READCONV(fptr)) {
SET_BINARY_MODE(fptr);
len = RSTRING_LEN(c);
#if SIZEOF_LONG > SIZEOF_INT
if (len > INT_MAX)
rb_raise(rb_eIOError, "ungetc failed");
#endif
make_readconv(fptr, (int)len);
if (fptr->cbuf.capa - fptr->cbuf.len < len)
rb_raise(rb_eIOError, "ungetc failed");
if (fptr->cbuf.off < len) {
MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.capa-fptr->cbuf.len,
fptr->cbuf.ptr+fptr->cbuf.off,
char, fptr->cbuf.len);
fptr->cbuf.off = fptr->cbuf.capa-fptr->cbuf.len;
}
fptr->cbuf.off -= (int)len;
fptr->cbuf.len += (int)len;
MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.off, RSTRING_PTR(c), char, len);
}
else {
NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
io_ungetbyte(c, fptr);
}
return Qnil;
}
|
#write(string, ...) ⇒ Integer
Writes the given strings to ios. The stream must be opened for writing. Arguments that are not a string will be converted to a string using to_s
. Returns the number of bytes written in total.
count = $stdout.write("This is", " a test\n")
puts "That was #{count} bytes of data"
produces:
This is a test
That was 15 bytes of data
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# File 'io.c', line 1934
static VALUE
io_write_m(int argc, VALUE *argv, VALUE io)
{
if (argc != 1) {
return io_writev(argc, argv, io);
}
else {
VALUE str = argv[0];
return io_write(io, str, 0);
}
}
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