glib/glib/gversion.c
Emmanuele Bassi 34aeeb7d64 Add flexible API version boundaries
There are cases when it should be possible to define at compile time
what range of functions and types should be used, in order to get,
or restrict, the compiler warnings for deprecated or newly added
types or functions.

For instance, if GLib introduces a deprecation warning on a type in
version 2.32, application code can decide to specify the minimum and
maximum boundary of the used API to be 2.30; when compiling against
a new version of GLib, this would produce the following results:

  - all deprecations introduced prior to 2.32 would emit compiler
    warnings when used by the application code;
  - all deprecations introduced in 2.32 would not emit compiler
    warnings when used by the application code;
  - all new symbols introduced in 2.32 would emit a compiler warning.

Using this scheme it should be possible to have fairly complex
situations, like the following one:

  assuming that an application is compiled with:
    GLIB_VERSION_MIN_REQUIRED = GLIB_VERSION_2_30
    GLIB_VERSION_MAX_ALLOWED  = GLIB_VERSION_2_32

  and a GLib header containing:

    void function_A (void) GLIB_DEPRECATED_IN_2_26;
    void function_B (void) GLIB_DEPRECATED_IN_2_28;
    void function_C (void) GLIB_DEPRECATED_IN_2_30;
    void function_D (void) GLIB_AVAILABLE_IN_2_32;
    void function_E (void) GLIB_AVAILABLE_IN_2_34;

  any application code using the above functions will get the following
  compiler warnings:

    function_A: deprecated symbol warning
    function_B: deprecated symbol warning
    function_C: no warning
    function_D: no warning
    function_E: undefined symbol warning

This means that it should be possible to gradually port code towards
non-deprecated API gradually, on a per-release basis.

https://bugzilla.gnome.org/show_bug.cgi?id=670542
2012-02-26 23:58:41 -05:00

158 lines
5.5 KiB
C

/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1998 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gversion.h"
/**
* SECTION:version
* @Title: Version Information
* @Short_description: variables and functions to check the GLib version
*
* GLib provides version information, primarily useful in configure
* checks for builds that have a configure script. Applications will
* not typically use the features described here.
*
* The GLib headers annotate deprecated APIs in a way that produces
* compiler warnings if these deprecated APIs are used. The warnings
* can be turned off by defining the macro %GLIB_DISABLE_DEPRECATION_WARNINGS
* before including the glib.h header.
*
* GLib also provides support for building applications against
* defined subsets of deprecated or new GLib APIs. Define the macro
* %GLIB_VERSION_MIN_REQUIRED to specify up to what version of GLib
* you want to receive warnings about deprecated APIs. Define the
* macro %GLIB_VERSION_MAX_ALLOWED to specify the newest version of
* GLib whose API you want to use.
*/
/**
* GLIB_MAJOR_VERSION:
*
* The major version number of the GLib library.
*
* Like #glib_major_version, but from the headers used at
* application compile time, rather than from the library
* linked against at application run time.
*/
/**
* GLIB_MINOR_VERSION:
*
* The minor version number of the GLib library.
*
* Like #gtk_minor_version, but from the headers used at
* application compile time, rather than from the library
* linked against at application run time.
*/
/**
* GLIB_MICRO_VERSION:
*
* The micro version number of the GLib library.
*
* Like #gtk_micro_version, but from the headers used at
* application compile time, rather than from the library
* linked against at application run time.
*/
/**
* GLIB_CHECK_VERSION:
* @major: the major version to check for
* @minor: the minor version to check for
* @micro: the micro version to check for
*
* Checks the version of the GLib library that is being compiled
* against.
*
* <example>
* <title>Checking the version of the GLib library</title>
* <programlisting>
* if (!GLIB_CHECK_VERSION (1, 2, 0))
* g_error ("GLib version 1.2.0 or above is needed");
* </programlisting>
* </example>
*
* See glib_check_version() for a runtime check.
*
* Returns: %TRUE if the version of the GLib header files
* is the same as or newer than the passed-in version.
*/
const guint glib_major_version = GLIB_MAJOR_VERSION;
const guint glib_minor_version = GLIB_MINOR_VERSION;
const guint glib_micro_version = GLIB_MICRO_VERSION;
const guint glib_interface_age = GLIB_INTERFACE_AGE;
const guint glib_binary_age = GLIB_BINARY_AGE;
/**
* glib_check_version:
* @required_major: the required major version.
* @required_minor: the required minor version.
* @required_micro: the required micro version.
*
* Checks that the GLib library in use is compatible with the
* given version. Generally you would pass in the constants
* #GLIB_MAJOR_VERSION, #GLIB_MINOR_VERSION, #GLIB_MICRO_VERSION
* as the three arguments to this function; that produces
* a check that the library in use is compatible with
* the version of GLib the application or module was compiled
* against.
*
* Compatibility is defined by two things: first the version
* of the running library is newer than the version
* @required_major.required_minor.@required_micro. Second
* the running library must be binary compatible with the
* version @required_major.required_minor.@required_micro
* (same major version.)
*
* Return value: %NULL if the GLib library is compatible with the
* given version, or a string describing the version mismatch.
* The returned string is owned by GLib and must not be modified
* or freed.
*
* Since: 2.6
*/
const gchar *
glib_check_version (guint required_major,
guint required_minor,
guint required_micro)
{
gint glib_effective_micro = 100 * GLIB_MINOR_VERSION + GLIB_MICRO_VERSION;
gint required_effective_micro = 100 * required_minor + required_micro;
if (required_major > GLIB_MAJOR_VERSION)
return "GLib version too old (major mismatch)";
if (required_major < GLIB_MAJOR_VERSION)
return "GLib version too new (major mismatch)";
if (required_effective_micro < glib_effective_micro - GLIB_BINARY_AGE)
return "GLib version too new (micro mismatch)";
if (required_effective_micro > glib_effective_micro)
return "GLib version too old (micro mismatch)";
return NULL;
}