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Exception: SystemCallError

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::StandardError, ::Exception
Instance Chain:
self, ::StandardError, ::Exception
Inherits: StandardError
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 Attribute Summary

::Exception - Inherited

.to_tty?

Returns true if exception messages will be sent to a terminal device.

Class Method Summary

::Exception - Inherited

.exception

Returns an exception object of the same class as self; useful for creating a similar exception, but with a different message.
.new

Returns a new exception object.

Instance Method Summary

::Exception - Inherited

#==

Returns whether object is the same class as self and its #message and #backtrace are equal to those of self.
#backtrace

Returns the backtrace (the list of code locations that led to the exception), as an array of strings.
#backtrace_locations

Returns the backtrace (the list of code locations that led to the exception), as an array of ::Thread::Backtrace::Location instances.
#cause

Returns the previous value of global variable $!, which may be nil (see Global Variables):
#detailed_message

Returns the message string with enhancements:
#exception

Returns an exception object of the same class as self; useful for creating a similar exception, but with a different message.
#full_message

Returns an enhanced message string:
#inspect

Returns a string representation of self:
#message

Returns #to_s.
#set_backtrace

Sets the backtrace value for self; returns the given value.
#to_s

Returns a string representation of self:

Constructor Details

.new(msg, errno = nil, func = nil) ⇒ system_call_error_subclass

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.

If only numeric object is given, it is treated as an ::Integer errno, and msg is omitted, otherwise the first argument msg is used as the additional error message.

SystemCallError.new(Errno::EPIPE::Errno)
#=> #<Errno::EPIPE: Broken pipe>

SystemCallError.new("foo")
#=> #<SystemCallError: unknown error - foo>

SystemCallError.new("foo", Errno::EPIPE::Errno)
#=> #<Errno::EPIPE: Broken pipe - foo>

If func is not nil, it is appended to the message with “ @ ”.

SystemCallError.new("foo", Errno::EPIPE::Errno, "here")
#=> #<Errno::EPIPE: Broken pipe @ here - foo>

A subclass of SystemCallError can also be instantiated via the new method of the subclass. See Errno.

[ GitHub ] 

  


# File 'error.c', line 3122



static VALUE
syserr_initialize(int argc, VALUE *argv, VALUE self)
{
    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;
}


  







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.


  



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# File 'error.c', line 3186



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);
    return RBOOL(FIXNUM_P(num) ? num == e : rb_equal(num, e));
}


  







Instance Method Details



  

    #errno  ⇒ Integer   



  

    

Return this SystemCallError’s error number.


  



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# File 'error.c', line 3172



static VALUE
syserr_errno(VALUE self)
{
    return rb_attr_get(self, id_errno);
}