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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
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; }
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.
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; }