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-spe‐
22 cific 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; how‐
26 ever, Glib is a binding to another software library, and this intro‐
27 duces some complexity. We have three versions that fully specify the
28 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 $Glib::VERSION
38 use Glib 1.040; # require at least version 1.040
39 Compile-time ("Bound") Library Version
41 This is the version of the GLib C library that was available when
42 the Perl module was compiled and installed. These version con‐
43 stants are equivalent to the version macros provided in the GLib C
44 headers. GLib uses a major.minor.micro convention, where even
45 minor versions are stable. (gtk2-perl does not officially support
46 unstable versions.)
47 Glib::MAJOR_VERSION
49 Glib::MINOR_VERSION
50 Glib::MICRO_VERSION
51 Glib->CHECK_VERSION($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
66 doing. Let's explain by example:
67 o Use the Perl module version for bindings support issues
69 You need to register a new enum for use as the type of an object
70 property. This is something you can do with all versions of the
71 underlying C library, but which wasn't supported in the Glib Perl
72 module until $Glib::VERSION >= 1.040.
73 o Use the bound version for library features
75 You want to call Glib::set_application_name to set a human-readable
76 name for your application (which is used by various parts of Gtk2
77 and Gnome2). g_set_application_name() (the underlying C function)
78 was added in version 2.2.0 of glib, and support for it was intro‐
79 duced into the Glib Perl module in Glib version 1.040. However,
80 you can build the Perl module against any stable 2.x.x version of
81 glib, so you might not have that function available even if your
82 Glib module is new enough!
83 Thus, you need to check two things to see if the this function is
84 available:
85 if ($Glib::VERSION >= 1.040 && Glib->CHECK_VERSION (2,2,0)) {
87 # it's available, and we can call it!
88 Glib::set_application_name ('My Cool Application');
89 }
90 Now what happens if you installed the Perl module when your system
92 had glib 2.0.6, and you upgraded glib to 2.4.1? Wouldn't
93 g_set_application_name() be available? Well, it's there, under the
94 hood, but the bindings were compiled when it wasn't there, so you
95 won't be able to call it! That's why we check the "bound" or com‐
96 pile-time version. By the way, to enable support for the new func‐
97 tion, you'd need to reinstall (or upgrade) the Perl module.
98 o Use the linked version for runtime work-arounds
100 Suppose there's a function whose API did not change, but whose
101 implementation had a bug in one version that was fixed in another
102 version. To determine whether you need to apply a workaround, you
103 would check the version that is actually being used at runtime.
104 if (Glib::major_version == 2 &&
106 Glib::minor_version == 2 &&
107 Glib::micro_version == 1) {
108 # work around bug that exists only in glib 2.2.1.
109 }
110 In practice, such situations are very rare.
112
114 boolean = Glib->CHECK_VERSION ($required_major, $required_minor,
115 $required_micro)
116 * $required_major (integer)
118 * $required_minor (integer)
119 * $required_micro (integer)
120 Provides a mechanism for checking the version information that Glib
122 was 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
128 compiled. See "Glib::MAJOR_VERSION", etc.
129 integer = Glib::MAJOR_VERSION
131 Provides access to the version information that Glib was compiled
133 against. Essentially equivalent to the #define's GLIB_MAJOR_VER‐
134 SION.
135 integer = Glib::MICRO_VERSION
137 Provides access to the version information that Glib was compiled
139 against. Essentially equivalent to the #define's GLIB_MICRO_VER‐
140 SION.
141 integer = Glib::MINOR_VERSION
143 Provides access to the version information that Glib was compiled
145 against. Essentially equivalent to the #define's GLIB_MINOR_VER‐
146 SION.
147 integer = Glib::major_version
149 Provides access to the version information that Glib is linked
151 against. Essentially equivalent to the global variable
152 glib_major_version.
153 integer = Glib::micro_version
155 Provides access to the version information that Glib is linked
157 against. Essentially equivalent to the global variable
158 glib_micro_version.
159 integer = Glib::minor_version
161 Provides access to the version information that Glib is linked
163 against. Essentially equivalent to the global variable
164 glib_minor_version.
165
167 Glib
168
170 Copyright (C) 2003-2007 by the gtk2-perl team.
171 This software is licensed under the LGPL. See Glib for a full notice.
173perl v5.8.8 2007-02-26 Glib::version(3)