Class: Process::Status

Inherits:
Object show all
Defined in:
process.c,
process.c

Overview

*******************************************************************

<code>Process::Status</code> encapsulates the information on the
status of a running or terminated system process. The built-in
variable <code>$?</code> is either +nil+ or a
<code>Process::Status</code> object.

   fork { exit 99 }   #=> 26557
   Process.wait       #=> 26557
   $?.class           #=> Process::Status
   $?.to_i            #=> 25344
   $? >> 8            #=> 99
   $?.stopped?        #=> false
   $?.exited?         #=> true
   $?.exitstatus      #=> 99

Posix systems record information on processes using a 16-bit
integer.  The lower bits record the process status (stopped,
exited, signaled) and the upper bits possibly contain additional
information (for example the program's return code in the case of
exited processes). Pre Ruby 1.8, these bits were exposed directly
to the Ruby program. Ruby now encapsulates these in a
<code>Process::Status</code> object. To maximize compatibility,
however, these objects retain a bit-oriented interface. In the
descriptions that follow, when we talk about the integer value of
_stat_, we're referring to this 16 bit value.

Instance Method Summary collapse

Instance Method Details

#&(num) ⇒ Fixnum

Logical AND of the bits in stat with num.

fork { exit 0x37 }
Process.wait
sprintf('%04x', $?.to_i)       #=> "3700"
sprintf('%04x', $? & 0x1e00)   #=> "1600"

Returns:


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# File 'process.c', line 462

static VALUE
pst_bitand(VALUE st1, VALUE st2)
{
    int status = PST2INT(st1) & NUM2INT(st2);

    return INT2NUM(status);
}

#==(other) ⇒ Boolean

Returns true if the integer value of stat equals other.

Returns:

  • (Boolean)

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# File 'process.c', line 442

static VALUE
pst_equal(VALUE st1, VALUE st2)
{
    if (st1 == st2) return Qtrue;
    return rb_equal(pst_to_i(st1), st2);
}

#>>(num) ⇒ Fixnum

Shift the bits in stat right num places.

fork { exit 99 }   #=> 26563
Process.wait       #=> 26563
$?.to_i            #=> 25344
$? >> 8            #=> 99

Returns:


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# File 'process.c', line 483

static VALUE
pst_rshift(VALUE st1, VALUE st2)
{
    int status = PST2INT(st1) >> NUM2INT(st2);

    return INT2NUM(status);
}

#coredump?Boolean

Returns true if stat generated a coredump when it terminated. Not available on all platforms.

Returns:

  • (Boolean)

Returns:

  • (Boolean)

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# File 'process.c', line 650

static VALUE
pst_wcoredump(VALUE st)
{
#ifdef WCOREDUMP
    int status = PST2INT(st);

    if (WCOREDUMP(status))
	return Qtrue;
    else
	return Qfalse;
#else
    return Qfalse;
#endif
}

#exited?Boolean

Returns true if stat exited normally (for example using an exit() call or finishing the program).

Returns:

  • (Boolean)

Returns:

  • (Boolean)

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# File 'process.c', line 581

static VALUE
pst_wifexited(VALUE st)
{
    int status = PST2INT(st);

    if (WIFEXITED(status))
	return Qtrue;
    else
	return Qfalse;
}

#exitstatusFixnum?

Returns the least significant eight bits of the return code of stat. Only available if exited? is true.

fork { }           #=> 26572
Process.wait       #=> 26572
$?.exited?         #=> true
$?.exitstatus      #=> 0

fork { exit 99 }   #=> 26573
Process.wait       #=> 26573
$?.exited?         #=> true
$?.exitstatus      #=> 99

Returns:


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# File 'process.c', line 612

static VALUE
pst_wexitstatus(VALUE st)
{
    int status = PST2INT(st);

    if (WIFEXITED(status))
	return INT2NUM(WEXITSTATUS(status));
    return Qnil;
}

#inspectString

Override the inspection method.

system("false")
p $?.inspect #=> "#<Process::Status: pid 12861 exit 1>"

Returns:


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# File 'process.c', line 413

static VALUE
pst_inspect(VALUE st)
{
    rb_pid_t pid;
    int status;
    VALUE vpid, str;

    vpid = pst_pid(st);
    if (NIL_P(vpid)) {
        return rb_sprintf("#<%s: uninitialized>", rb_class2name(CLASS_OF(st)));
    }
    pid = NUM2PIDT(vpid);
    status = PST2INT(st);

    str = rb_sprintf("#<%s: ", rb_class2name(CLASS_OF(st)));
    pst_message(str, pid, status);
    rb_str_cat2(str, ">");
    return str;
}

#pidFixnum

Returns the process ID that this status object represents.

fork { exit }   #=> 26569
Process.wait    #=> 26569
$?.pid          #=> 26569

Returns:


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# File 'process.c', line 334

static VALUE
pst_pid(VALUE st)
{
    return rb_attr_get(st, rb_intern("pid"));
}

#signaled?Boolean

Returns true if stat terminated because of an uncaught signal.

Returns:

  • (Boolean)

Returns:

  • (Boolean)

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# File 'process.c', line 540

static VALUE
pst_wifsignaled(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSIGNALED(status))
	return Qtrue;
    else
	return Qfalse;
}

#stopped?Boolean

Returns true if this process is stopped. This is only returned if the corresponding wait call had the WUNTRACED flag set.

Returns:

  • (Boolean)

Returns:

  • (Boolean)

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# File 'process.c', line 501

static VALUE
pst_wifstopped(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSTOPPED(status))
	return Qtrue;
    else
	return Qfalse;
}

#stopsigFixnum?

Returns the number of the signal that caused stat to stop (or nil if self is not stopped).

Returns:


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# File 'process.c', line 521

static VALUE
pst_wstopsig(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSTOPPED(status))
	return INT2NUM(WSTOPSIG(status));
    return Qnil;
}

#success?true, ...

Returns true if stat is successful, false if not. Returns nil if exited? is not true.

Returns:

  • (true, false, nil)

Returns:

  • (Boolean)

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# File 'process.c', line 631

static VALUE
pst_success_p(VALUE st)
{
    int status = PST2INT(st);

    if (!WIFEXITED(status))
	return Qnil;
    return WEXITSTATUS(status) == EXIT_SUCCESS ? Qtrue : Qfalse;
}

#termsigFixnum?

Returns the number of the signal that caused stat to terminate (or nil if self was not terminated by an uncaught signal).

Returns:


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# File 'process.c', line 561

static VALUE
pst_wtermsig(VALUE st)
{
    int status = PST2INT(st);

    if (WIFSIGNALED(status))
	return INT2NUM(WTERMSIG(status));
    return Qnil;
}

#to_iFixnum #to_intFixnum

Returns the bits in stat as a Fixnum. Poking around in these bits is platform dependent.

fork { exit 0xab }         #=> 26566
Process.wait               #=> 26566
sprintf('%04x', $?.to_i)   #=> "ab00"

Overloads:


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# File 'process.c', line 315

static VALUE
pst_to_i(VALUE st)
{
    return rb_iv_get(st, "status");
}

#to_sString

Show pid and exit status as a string.

system("false")
p $?.to_s         #=> "pid 12766 exit 1"

Returns:


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# File 'process.c', line 386

static VALUE
pst_to_s(VALUE st)
{
    rb_pid_t pid;
    int status;
    VALUE str;

    pid = NUM2PIDT(pst_pid(st));
    status = PST2INT(st);

    str = rb_str_buf_new(0);
    pst_message(str, pid, status);
    return str;
}