Exception: SystemCallError

Inherits:
StandardError show all
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 collapse

Instance Method Summary collapse

Methods inherited from Exception

#==, #backtrace, 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.


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# File 'error.c', line 1220

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

    if (klass == rb_eSystemCallError) {
	st_data_t data = (st_data_t)klass;
	rb_scan_args(argc, argv, "11", &mesg, &error);
	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(self)->klass = klass;
	}
    }
    else {
	rb_scan_args(argc, argv, "01", &mesg);
	error = rb_const_get(klass, rb_intern("Errno"));
    }
    if (!NIL_P(error)) err = strerror(NUM2INT(error));
    else err = "unknown error";
    if (!NIL_P(mesg)) {
	rb_encoding *le = rb_locale_encoding();
	VALUE str = StringValue(mesg);
	rb_encoding *me = rb_enc_get(mesg);

	mesg = rb_sprintf("%s - %"PRIsVALUE, err, mesg);
	if (le != me && rb_enc_asciicompat(me)) {
	    le = me;
	}/* else assume err is non ASCII string. */
	OBJ_INFECT(mesg, str);
	rb_enc_associate(mesg, le);
    }
    else {
	mesg = rb_str_new2(err);
	rb_enc_associate(mesg, rb_locale_encoding());
    }
    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)

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# File 'error.c', line 1293

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

#errnoFixnum

Return this SystemCallError's error number.

Returns:


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# File 'error.c', line 1279

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