Exception: SystemCallError

Inherits:

StandardError

• Object
• Exception
• StandardError
• SystemCallError

Defined in:

error.c,
error.c

Overview

SystemCallError is the base class for all low-level platform-dependent errors.

The errors available on the current platform are subclasses of SystemCallError and are defined in the Errno module.

File.open("does/not/exist")

raises the exception:

Errno::ENOENT: No such file or directory - does/not/exist

Class Method Summary

• .===(other) ⇒ Boolean

  Return true if the receiver is a generic SystemCallError, or if the error numbers self and other are the same.

Instance Method Summary

• #errno ⇒ Fixnum

  Return this SystemCallError’s error number.

• #new(msg, errno) ⇒ Object constructor

  If errno corresponds to a known system error code, constructs the appropriate Errno class for that error, otherwise constructs a generic SystemCallError object.

Methods inherited from Exception

#==, #backtrace, #backtrace_locations, #cause, #exception, exception, #inspect, #message, #set_backtrace, #to_s

Constructor Details

#new(msg, errno) ⇒ Object

If errno corresponds to a known system error code, constructs the appropriate Errno class for that error, otherwise constructs a generic SystemCallError object. The error number is subsequently available via the errno method.

# File 'error.c', line 1373

static VALUE
syserr_initialize(int argc, VALUE *argv, VALUE self)
{
#if !defined(_WIN32)
    char *strerror();
#endif
    const char *err;
    VALUE mesg, error, func, errmsg;
    VALUE klass = rb_obj_class(self);

    if (klass == rb_eSystemCallError) {
	st_data_t data = (st_data_t)klass;
	rb_scan_args(argc, argv, "12", &mesg, &error, &func);
	if (argc == 1 && FIXNUM_P(mesg)) {
	    error = mesg; mesg = Qnil;
	}
	if (!NIL_P(error) && st_lookup(syserr_tbl, NUM2LONG(error), &data)) {
	    klass = (VALUE)data;
	    /* change class */
	    if (!RB_TYPE_P(self, T_OBJECT)) { /* insurance to avoid type crash */
		rb_raise(rb_eTypeError, "invalid instance type");
	    }
	    RBASIC_SET_CLASS(self, klass);
	}
    }
    else {
	rb_scan_args(argc, argv, "02", &mesg, &func);
	error = rb_const_get(klass, rb_intern("Errno"));
    }
    if (!NIL_P(error)) err = strerror(NUM2INT(error));
    else err = "unknown error";

    errmsg = rb_enc_str_new_cstr(err, rb_locale_encoding());
    if (!NIL_P(mesg)) {
	VALUE str = StringValue(mesg);

	if (!NIL_P(func)) rb_str_catf(errmsg, " @ %"PRIsVALUE, func);
	rb_str_catf(errmsg, " - %"PRIsVALUE, str);
	OBJ_INFECT(errmsg, mesg);
    }
    mesg = errmsg;

    rb_call_super(1, &mesg);
    rb_iv_set(self, "errno", error);
    return self;
}

Class Method Details

.===(other) ⇒ Boolean

Return true if the receiver is a generic SystemCallError, or if the error numbers self and other are the same.

Returns:

• (Boolean)

# File 'error.c', line 1441

static VALUE
syserr_eqq(VALUE self, VALUE exc)
{
    VALUE num, e;
    ID en;

    CONST_ID(en, "errno");

    if (!rb_obj_is_kind_of(exc, rb_eSystemCallError)) {
	if (!rb_respond_to(exc, en)) return Qfalse;
    }
    else if (self == rb_eSystemCallError) return Qtrue;

    num = rb_attr_get(exc, rb_intern("errno"));
    if (NIL_P(num)) {
	num = rb_funcall(exc, en, 0, 0);
    }
    e = rb_const_get(self, rb_intern("Errno"));
    if (FIXNUM_P(num) ? num == e : rb_equal(num, e))
	return Qtrue;
    return Qfalse;
}

Instance Method Details

#errno ⇒ Fixnum

Return this SystemCallError’s error number.

Returns:

• (Fixnum)

# File 'error.c', line 1427

static VALUE
syserr_errno(VALUE self)
{
    return rb_attr_get(self, rb_intern("errno"));
}