1Glib::version(3) User Contributed Perl Documentation Glib::version(3)
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6 Glib::version - Library Versioning Utilities
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9 # require at least version 1.021 of the Glib module
10 use Glib '1.021';
11 # g_set_application_name() was introduced in GLib 2.2.0, and
13 # first supported by version 1.040 of the Glib Perl module.
14 if ($Glib::VERSION >= 1.040 and Glib->CHECK_VERSION (2,2,0)) {
15 Glib::set_application_name ('My Cool Program');
16 }
17
19 Both the Glib module and the GLib C library are works-in-progress, and
20 their interfaces grow over time. As more features are added to each,
21 and your code uses those new features, you will introduce version-
22 specific dependencies, and naturally, you'll want to be able to code
23 around them. Enter the versioning API.
24 For simple Perl modules, a single version number is sufficient;
26 however, Glib is a binding to another software library, and this
27 introduces some complexity. We have three versions that fully specify
28 the API available to you.
29 Perl Bindings Version
31 Perl modules use a version number, and Glib is no exception.
32 $Glib::VERSION is the version of the current Glib module. By ad
33 hoc convention, gtk2-perl modules generally use version numbers in
34 the form x.yyz, where even yy values denote stable releases and z
35 is a patchlevel.
36 $Glib::VERSION
38 use Glib 1.040; # require at least version 1.040
39 Compile-time ("Bound") Library Version
41 This is the version of the GLib C library that was available when
42 the Perl module was compiled and installed. These version
43 constants are equivalent to the version macros provided in the GLib
44 C headers. GLib uses a major.minor.micro convention, where even
45 minor versions are stable. (gtk2-perl does not officially support
46 unstable versions.)
47 Glib::MAJOR_VERSION
49 Glib::MINOR_VERSION
50 Glib::MICRO_VERSION
51 Glib->CHECK_VERSION($maj,$min,$mic)
52 Run-time ("Linked") Library Version
54 This is the version of the GLib C library that is available at run
55 time; it may be newer than the compile-time version, but should
56 never be older. These are equivalent to the version variables
57 exported by the GLib C library.
58 Glib::major_version
60 Glib::minor_version
61 Glib::micro_version
62 Which one do I use when?
64 Where do you use which version? It depends entirely on what you're
65 doing. Let's explain by example:
66 o Use the Perl module version for bindings support issues
68 You need to register a new enum for use as the type of an object
69 property. This is something you can do with all versions of the
70 underlying C library, but which wasn't supported in the Glib Perl
71 module until $Glib::VERSION >= 1.040.
72 o Use the bound version for library features
74 You want to call Glib::set_application_name to set a human-readable
75 name for your application (which is used by various parts of Gtk2
76 and Gnome2). g_set_application_name() (the underlying C function)
77 was added in version 2.2.0 of glib, and support for it was
78 introduced into the Glib Perl module in Glib version 1.040.
79 However, you can build the Perl module against any stable 2.x.x
80 version of glib, so you might not have that function available even
81 if your Glib module is new enough!
82 Thus, you need to check two things to see if the this function is
83 available:
84 if ($Glib::VERSION >= 1.040 && Glib->CHECK_VERSION (2,2,0)) {
86 # it's available, and we can call it!
87 Glib::set_application_name ('My Cool Application');
88 }
89 Now what happens if you installed the Perl module when your system
91 had glib 2.0.6, and you upgraded glib to 2.4.1? Wouldn't
92 g_set_application_name() be available? Well, it's there, under the
93 hood, but the bindings were compiled when it wasn't there, so you
94 won't be able to call it! That's why we check the "bound" or
95 compile-time version. By the way, to enable support for the new
96 function, you'd need to reinstall (or upgrade) the Perl module.
97 o Use the linked version for runtime work-arounds
99 Suppose there's a function whose API did not change, but whose
100 implementation had a bug in one version that was fixed in another
101 version. To determine whether you need to apply a workaround, you
102 would check the version that is actually being used at runtime.
103 if (Glib::major_version == 2 &&
105 Glib::minor_version == 2 &&
106 Glib::micro_version == 1) {
107 # work around bug that exists only in glib 2.2.1.
108 }
109 In practice, such situations are very rare.
111
113 boolean = Glib->CHECK_VERSION ($required_major, $required_minor,
114 $required_micro)
115 · $required_major (integer)
116 · $required_minor (integer)
118 · $required_micro (integer)
120 Provides a mechanism for checking the version information that Glib was
122 compiled against. Essentially equvilent to the macro
123 GLIB_CHECK_VERSION.
124 (MAJOR, MINOR, MICRO) = Glib->GET_VERSION_INFO
126 Shorthand to fetch as a list the glib version for which Glib was
127 compiled. See "Glib::MAJOR_VERSION", etc.
128 integer = Glib::MAJOR_VERSION
130 Provides access to the version information that Glib was compiled
131 against. Essentially equivalent to the #define's GLIB_MAJOR_VERSION.
132 integer = Glib::MICRO_VERSION
134 Provides access to the version information that Glib was compiled
135 against. Essentially equivalent to the #define's GLIB_MICRO_VERSION.
136 integer = Glib::MINOR_VERSION
138 Provides access to the version information that Glib was compiled
139 against. Essentially equivalent to the #define's GLIB_MINOR_VERSION.
140 integer = Glib::major_version
142 Provides access to the version information that Glib is linked against.
143 Essentially equivalent to the global variable glib_major_version.
144 integer = Glib::micro_version
146 Provides access to the version information that Glib is linked against.
147 Essentially equivalent to the global variable glib_micro_version.
148 integer = Glib::minor_version
150 Provides access to the version information that Glib is linked against.
151 Essentially equivalent to the global variable glib_minor_version.
152
154 Glib
155
157 Copyright (C) 2003-2009 by the gtk2-perl team.
158 This software is licensed under the LGPL. See Glib for a full notice.
160perl v5.12.1 2010-07-07 Glib::version(3)