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; if (!rb_obj_is_kind_of(exc, rb_eSystemCallError)) { if (!rb_respond_to(exc, id_errno)) return Qfalse; } else if (self == rb_eSystemCallError) return Qtrue; num = rb_attr_get(exc, id_errno); if (NIL_P(num)) { num = rb_funcallv(exc, id_errno, 0, 0); } e = rb_const_get(self, id_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, 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, id_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); } mesg = errmsg; rb_call_super(1, &mesg); rb_ivar_set(self, id_errno, error); return self; }