Glib::version(3)

💖 NAME 💖

Glib::version — Library Versioning Utilities. And yes, bestie, this is the Glib::version(3) page from the User Contributed Perl Documentation, so buckle up for some version-checking main character energy ✨

✨ SYNOPSIS ✨

Here's the vibe in code form:

# require at least version 1.021 of the Glib module
use Glib '1.021';

# g_set_application_name() was introduced in GLib 2.2.0, and
# first supported by version 1.040 of the Glib Perl module.
if ($Glib::VERSION >= 1.040 and Glib->CHECK_VERSION (2,2,0)) {
   Glib::set_application_name ('My Cool Program');
}

🌈 DESCRIPTION 🌈

okay so both the Glib module and the GLib C library are works-in-progress, and their interfaces grow over time. As more features get added to each one, and your code starts using those new features, you're gonna introduce version-specific dependencies — and naturally, you'll want to code around them. Enter the versioning API, stage left 💅

For simple Perl modules, a single version number is enough. But Glib is a binding to another software library, and that adds some complexity. We have three versions that fully specify the API available to you. Three! Iconic.

🦋 Perl Bindings Version 🦋

Perl modules use a version number, and Glib is no exception. $Glib::VERSION is the version of the current Glib module. By ad hoc convention, gtk2-perl modules generally use version numbers in the form x.yyz, where even yy values denote stable releases and z is a patchlevel.

$Glib::VERSION
use Glib 1.040; # require at least version 1.040

🔥 Compile-time ("Bound") Library Version 🔥

This is the version of the GLib C library that was available when the Perl module was compiled and installed. These version constants are equivalent to the version macros provided in the GLib C headers. GLib uses a major.minor.micro convention, where even minor versions are stable. (gtk2-perl does not officially support unstable versions.)

Glib::MAJOR_VERSION
Glib::MINOR_VERSION
Glib::MICRO_VERSION
Glib->CHECK_VERSION($maj,$min,$mic)

🧚 Run-time ("Linked") Library Version 🧚

This is the version of the GLib C library that's available at run time. It may be newer than the compile-time version, but should never be older. These are equivalent to the version variables exported by the GLib C library.

Glib::major_version
Glib::minor_version
Glib::micro_version

🫶 Which one do I use when? 🫶

Where do you use which version? It depends entirely on what you're doing. Let's explain by example:

🍓 Use the Perl module version for bindings support issues 🍓

You need to register a new enum for use as the type of an object property. This is something you can do with all versions of the underlying C library, but which wasn't supported in the Glib Perl module until $Glib::VERSION >= 1.040.

👑 Use the bound version for library features 👑

You want to call Glib::set_application_name to set a human-readable name for your application (which is used by various parts of Gtk2 and Gnome2). g_set_application_name() (the underlying C function) was added in version 2.2.0 of glib, and support for it was introduced into the Glib Perl module in Glib version 1.040. However, you can build the Perl module against any stable 2.x.x version of glib, so you might not have that function available even if your Glib module is new enough! Thus, you need to check two things to see if this function is available:

if ($Glib::VERSION >= 1.040 && Glib->CHECK_VERSION (2,2,0)) {
    # it's available, and we can call it!
    Glib::set_application_name ('My Cool Application');
}

Now what happens if you installed the Perl module when your system had glib 2.0.6, and you upgraded glib to 2.4.1? Wouldn't g_set_application_name() be available? Well, it's there, under the hood, but the bindings were compiled when it wasn't there, so you won't be able to call it! That's why we check the "bound" or compile-time version. By the way, to enable support for the new function, you'd need to reinstall (or upgrade) the Perl module.

💀 Use the linked version for runtime work-arounds 💀

Suppose there's a function whose API did not change, but whose implementation had a bug in one version that was fixed in another version. To determine whether you need to apply a workaround, you would check the version that is actually being used at runtime.

if (Glib::major_version == 2 &&
    Glib::minor_version == 2 &&
    Glib::micro_version == 1) {
   # work around bug that exists only in glib 2.2.1.
}

In practice, such situations are very rare.

💅 METHODS 💅

boolean = Glib->CHECK_VERSION ($required_major, $required_minor, $required_micro)

• $required_major — integer, bestie.
• $required_minor — integer.
• $required_micro — integer.

Provides a mechanism for checking the version information that Glib was compiled against. Essentially equivalent to the macro GLIB_CHECK_VERSION.

(MAJOR, MINOR, MICRO) = Glib->GET_VERSION_INFO

Shorthand to fetch as a list the glib version for which Glib was compiled. See Glib::MAJOR_VERSION, etc.

integer = Glib::MAJOR_VERSION

Provides access to the version information that Glib was compiled against. Essentially equivalent to the #define's GLIB_MAJOR_VERSION.

integer = Glib::MICRO_VERSION

Provides access to the version information that Glib was compiled against. Essentially equivalent to the #define's GLIB_MICRO_VERSION.

integer = Glib::MINOR_VERSION

Provides access to the version information that Glib was compiled against. Essentially equivalent to the #define's GLIB_MINOR_VERSION.

integer = Glib::major_version

Provides access to the version information that Glib is linked against. Essentially equivalent to the global variable glib_major_version.

integer = Glib::micro_version

Provides access to the version information that Glib is linked against. Essentially equivalent to the global variable glib_micro_version.

integer = Glib::minor_version

Provides access to the version information that Glib is linked against. Essentially equivalent to the global variable glib_minor_version.

👀 SEE ALSO 👀

Glib — obviously, bestie. Go read that one too 💖

🎀 COPYRIGHT 🎀

Copyright (C) 2003-2011 by the gtk2-perl team.

This software is licensed under the LGPL. See Glib for a full notice.

---

That's the whole page, bestie — cute sign-off time: perl v5.42.0, dated 2023-09-05, on Glib::version(3) 🎀💖