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.IX Title "Glib::Error 3"
.TH Glib::Error 3 2025-07-13 "perl v5.42.0" "User Contributed Perl Documentation"
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.nh
.SH NAME
Glib::Error \-  Exception Objects based on GError
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 10
\&  eval {
\&     my $pixbuf = Gtk2::Gdk::Pixbuf\->new_from_file ($filename);
\&     $image\->set_from_pixbuf ($pixbuf);
\&  };
\&  if ($@) {
\&     print "$@\en";
\&     if (Glib::Error::matches ($@, \*(AqGtk2::Gdk::Pixbuf::Error\*(Aq,
\&                                   \*(Aqunknown\-format\*(Aq)) {
\&        change_format_and_try_again ();
\&     } elsif (Glib::Error::matches ($@, \*(AqGlib::File::Error\*(Aq, \*(Aqnoent\*(Aq)) {
\&        change_source_dir_and_try_again ();
\&     } else {
\&        # don\*(Aqt know how to handle this
\&        die $@;
\&     }
\&  }
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Gtk2\-Perl translates GLib\*(Aqs GError runtime errors into Perl exceptions, by
creating exception objects based on Glib::Error.  Glib::Error overloads the
stringification operator, so a Glib::Error object will act like a string if
used with \fBprint()\fR or \fBwarn()\fR, so most code using $@ will not even know the
difference.
.PP
The point of having exception objects, however, is that the error messages
in GErrors are often localized with NLS translation.  Thus, it\*(Aqs not good
for your code to attempt to handle errors by string matching on the the 
error message.  Glib::Error provides a way to get to the deterministic
error code.
.PP
You will typically deal with objects that inherit from Glib::Error, such as
Glib::Convert::Error, Glib::File::Error, Gtk2::Gdk::Pixbuf::Error, etc; these
classes are provided by the libraries that define the error domains.  However,
it is possible to get a base Glib::Error when the bindings encounter an unknown
or unbound error domain.  The interface used here degrades nicely in such a
situation, but in general you should submit a bug report to the binding
maintainer if you get such an exception.
.SH HIERARCHY
.IX Header "HIERARCHY"
.Vb 2
\&  Glib::Boxed
\&  +\-\-\-\-Glib::Error
.Ve
.SH METHODS
.IX Header "METHODS"
.ie n .SS "scalar = Glib::Error::new ($class, $code, $message)"
.el .SS "scalar = Glib::Error::new ($class, \f(CW$code\fP, \f(CW$message\fP)"
.IX Subsection "scalar = Glib::Error::new ($class, $code, $message)"
.ie n .SS "scalar = $class\->\fBnew\fP ($code, $message)"
.el .SS "scalar = \f(CW$class\fP\->\fBnew\fP ($code, \f(CW$message\fP)"
.IX Subsection "scalar = $class->new ($code, $message)"
.IP \(bu 4
\&\f(CW$code\fR (Glib::Enum) an enumeration value, depends on \fR\f(CI$class\fR\fI\fR
.IP \(bu 4
\&\f(CW$message\fR (string)
.PP
Create a new exception object of type \fR\f(CI$class\fR\fI\fR, where \fI\fR\f(CI$class\fR\fI\fR is associated
with a GError domain.  \fI\fR\f(CI$code\fR\fI\fR should be a value from the enumeration type
associated with this error domain.  \fI\fR\f(CI$message\fR\fI\fR can be anything you like, but
should explain what happened from the point of view of a user.
.ie n .SS "integer = $error\->\fBcode\fP"
.el .SS "integer = \f(CW$error\fP\->\fBcode\fP"
.IX Subsection "integer = $error->code"
This is the numeric error code.  Normally, you\*(Aqll want to use \f(CW\*(C`value\*(C'\fR instead,
for readability.
.ie n .SS "string = $error\->\fBdomain\fP"
.el .SS "string = \f(CW$error\fP\->\fBdomain\fP"
.IX Subsection "string = $error->domain"
The error domain.  You normally do not need this, as the object will be blessed
into a corresponding class.
.ie n .SS "string = $error\->\fBlocation\fP"
.el .SS "string = \f(CW$error\fP\->\fBlocation\fP"
.IX Subsection "string = $error->location"
The source line and file closest to the emission of the exception, in the same
format that you\*(Aqd get from \fBcroak()\fR or \fBdie()\fR.
.PP
If there\*(Aqs non\-ascii characters in the filename Perl leaves them as
raw bytes, so you may have to put the string through
Glib::filename_display_name for a wide\-char form.
.ie n .SS "boolean = $error\->\fBmatches\fP ($domain, $code)"
.el .SS "boolean = \f(CW$error\fP\->\fBmatches\fP ($domain, \f(CW$code\fP)"
.IX Subsection "boolean = $error->matches ($domain, $code)"
.IP \(bu 4
\&\f(CW$domain\fR (string)
.IP \(bu 4
\&\f(CW$code\fR (scalar)
.PP
Returns true if the exception in \fR\f(CI$error\fR\fI\fR matches the given \fI\fR\f(CI$domain\fR\fI\fR and
\&\fI\fR\f(CI$code\fR\fI\fR.  \fI\fR\f(CI$domain\fR\fI\fR may be a class name or domain quark (that is, the real
string used in C).  \fI\fR\f(CI$code\fR\fI\fR may be an integer value or an enum nickname;
the enum type depends on the value of \fI\fR\f(CI$domain\fR\fI\fR.
.ie n .SS "string = $error\->\fBmessage\fP"
.el .SS "string = \f(CW$error\fP\->\fBmessage\fP"
.IX Subsection "string = $error->message"
The error message.  This may be localized, as it is intended to be shown to a
user.
.ie n .SS "Glib::Error::register ($package, $enum_package)"
.el .SS "Glib::Error::register ($package, \f(CW$enum_package\fP)"
.IX Subsection "Glib::Error::register ($package, $enum_package)"
.IP \(bu 4
\&\f(CW$package\fR (string) class name to register as a Glib::Error.
.IP \(bu 4
\&\f(CW$enum_package\fR (string) class name of the enum type to use for this domain\*(Aqs error codes.
.PP
Register a new error domain.  Glib::Error will be added @\fIpackage\fR::ISA for
you.  \fIenum_package\fR must be a valid Glib::Enum type, either from a C library
or registered with \f(CW\*(C`Glib::Type::register_enum\*(C'\fR.  After registering an
error domain, you can create or throw exceptions of this type.
.ie n .SS "scalar = Glib::Error::throw ($class, $code, $message)"
.el .SS "scalar = Glib::Error::throw ($class, \f(CW$code\fP, \f(CW$message\fP)"
.IX Subsection "scalar = Glib::Error::throw ($class, $code, $message)"
.ie n .SS "scalar = $class\->\fBthrow\fP ($code, $message)"
.el .SS "scalar = \f(CW$class\fP\->\fBthrow\fP ($code, \f(CW$message\fP)"
.IX Subsection "scalar = $class->throw ($code, $message)"
.IP \(bu 4
\&\f(CW$code\fR (Glib::Enum) an enumeration value, depends on \fR\f(CI$class\fR\fI\fR
.IP \(bu 4
\&\f(CW$message\fR (string)
.PP
Throw an exception with a Glib::Error exception object.
Equivalent to \f(CW\*(C`croak (Glib::Error::new ($class, $code, $message));\*(C'\fR.
.ie n .SS "string = $error\->\fBvalue\fP"
.el .SS "string = \f(CW$error\fP\->\fBvalue\fP"
.IX Subsection "string = $error->value"
The enumeration value nickname of the integer value in \f(CW\*(C`$error\->code\*(C'\fR, 
according to this error domain.  This will not be available if the error
object is a base Glib::Error, because the bindings will have no idea how to
get to the correct nickname.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Glib, Glib::Boxed
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright (C) 2003\-2011 by the gtk2\-perl team.
.PP
This software is licensed under the LGPL.  See Glib for a full notice.