Exception: SystemCallError

Inherits:

StandardError

• Object
• Exception
• StandardError
• SystemCallError

Defined in:

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, #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'

/*
 * call-seq:
 *   SystemCallError.new(msg, errno)  -> system_call_error_subclass
 *
 * If _errno_ corresponds to a known system error code, constructs
 * the appropriate <code>Errno</code> class for that error, otherwise
 * constructs a generic <code>SystemCallError</code> object. The
 * error number is subsequently available via the <code>errno</code>
 * method.
 */

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) {
    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), &klass)) {
        /* change class */
        if (TYPE(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)) {
    VALUE str = mesg;

    StringValue(str);
    mesg = rb_sprintf("%s - %.*s", err,
              (int)RSTRING_LEN(str), RSTRING_PTR(str));
    }
    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)

# File 'error.c'

/*
 * call-seq:
 *   system_call_error === other  -> true or false
 *
 * Return +true+ if the receiver is a generic +SystemCallError+, or
 * if the error numbers +self+ and _other_ are the same.
 */

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'

/*
 * call-seq:
 *   system_call_error.errno   -> fixnum
 *
 * Return this SystemCallError's error number.
 */

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