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Low-level core library that forms the basis for projects such as GTK+ and GNOME.
26,563 Commits 296 Branches 577 Tags 135 MiB
C 95.3%
Python 2.4%
Meson 1.3%
Objective-C 0.3%
Shell 0.2%
Other 0.5%
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Thomas Haller 938a1caf89 gtype: avoid "-Wcast-align" warning with optimized G_TYPE_CHECK_INSTANCE_CAST() 
We can get a "-Wcast-align", if the target type that we cast to ("ct") has a
larger alignment than GTypeInstance.

That can happen on i686 architecture, if the GObject type has larger
alignment than the parent struct (or GObject). Since on i686, embeding
a "long long" or a "long double" in a struct still does not increase
the alignment beyond 4 bytes, this usually only happens when using the
__attribute__() to increase the alignment (or to have a field that has
the alignment increased).

It can happen on x86_64 when having a "long double" field.

The compiler warning is hard to avoid but not very useful, because it purely
operates on the pointer types at compile time. G_TYPE_CHECK_INSTANCE_CAST()
instead asserts (in non-optimized mode) that the pointer really points
to the expected GTypeInstance (and if that's the case, then the alignment
should be suitable already).

This is like in commit ed553e8e30 ('gtype: Eliminate -Wcast-align warnings
with G_TYPE_CHECK_INSTANCE_CAST'). But also fix the optimized code path.

With the unpatched G_TYPE_CHECK_INSTANCE_CAST() macro, the unit test would
now show the problem (with gcc-9.3.1-2.fc30.i686 or
gcc-12.2.1-4.fc37.x86_64):

  $ export G_DISABLE_CAST_CHECKS=1
  $ export CFLAGS='-Wcast-align=strict'
  $ meson build
  $ ninja -C build
  ...
  In file included from ../gobject/gobject.h:26,
                   from ../gobject/gbinding.h:31,
                   from ../glib/glib-object.h:24,
                   from ../gobject/tests/objects-refcount1.c:2:
  ../gobject/tests/objects-refcount1.c: In function ‘my_test_dispose’:
  ../gobject/gtype.h:2523:42: warning: cast increases required alignment of target type [-Wcast-align]
   2523 | #  define _G_TYPE_CIC(ip, gt, ct)       ((ct*) ip)
        |                                          ^
  ../gobject/gtype.h:517:66: note: in expansion of macro ‘_G_TYPE_CIC’
    517 | #define G_TYPE_CHECK_INSTANCE_CAST(instance, g_type, c_type)    (_G_TYPE_CIC ((instance), (g_type), c_type))
        |                                                                  ^~~~~~~~~~~
  ../gobject/tests/objects-refcount1.c:9:37: note: in expansion of macro ‘G_TYPE_CHECK_INSTANCE_CAST’
      9 | #define MY_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
        |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~
  ../gobject/tests/objects-refcount1.c:96:10: note: in expansion of macro ‘MY_TEST’
     96 |   test = MY_TEST (object);
        |          ^~~~~~~
2022-12-16 20:48:06 +01:00
.gitlab-ci ci: Don’t fail if testlog-unstable_tests.junit.xml doesn’t exist on MSVC 2022-12-08 15:27:24 +00:00
.reuse docs: Add licensing/copyright data to GVariant specification 2022-11-08 15:46:16 +00:00
docs gmenumodel: disallow exporting large menus on the bus 2022-12-14 15:42:14 +00:00
fuzzing fuzzing: Add a fuzz test for g_utf8_validate() 2022-11-07 13:20:32 +00:00
gio Merge branch '861-dbus-menu-model-robustness' into 'main' 2022-12-14 16:18:07 +00:00
glib gtestutils: Check for failure to setenv() and return 2022-12-14 15:11:10 +00:00
gmodule Fix gmodule/COPYING symlink path 2022-11-28 12:13:21 +02:00
gobject gtype: avoid "-Wcast-align" warning with optimized G_TYPE_CHECK_INSTANCE_CAST() 2022-12-16 20:48:06 +01:00
gthread gthread: Fully initialize GThreadFunctions structure in test 2022-11-14 09:43:29 +00:00
LICENSES Add a SPDX LicenseRef for the license historically used for tests 2022-11-02 12:34:19 +00:00
m4macros m4macros: Increment serial number of glib-2.0.m4 2021-01-27 11:55:37 +00:00
po Add Interlingue translation 2022-12-12 00:16:24 +00:00
subprojects replace pcre1 with pcre2 2022-07-12 11:46:34 +00:00
tests Convert tests/assert-msg-test* to glib/tests/assert-msg-test* 2022-06-28 11:19:21 +01:00
tools tools: Reformat gen-visibility-macros.py with black 2022-10-14 18:15:25 +01:00
.clang-format CI: Code check formating in CI 2019-11-21 14:03:01 -06:00
.dir-locals.el Add .dir-locals.el to tell Emacs users not to use tabs for C 2012-07-30 04:09:08 -04:00
.editorconfig docs: Add .editorconfig file 2021-10-28 14:47:53 +01:00
.gitignore docs: Move INSTALL.in to INSTALL.md 2022-05-11 13:02:49 +01:00
.gitlab-ci.yml Revert "build: Bump Meson dependency to 0.64.0" 2022-11-24 12:10:07 +00:00
.gitmodules ci: Update git paths to reflect new GitLab URI 2022-11-02 16:49:51 +00:00
.lcovrc build: Move lcovrc file to root so it’s picked up by Meson 2022-04-28 11:57:45 +01:00
CODE_OF_CONDUCT.md docs: Add a code of conduct document 2022-05-11 12:30:58 +01:00
CONTRIBUTING.md ci: Update git paths to reflect new GitLab URI 2022-11-02 16:49:51 +00:00
COPYING docs: Add all used licenses in a REUSE-compatible directory 2022-05-17 17:23:34 +01:00
glib.doap docs: Sync glib.doap to set of users listed in CODEOWNERS 2022-06-22 15:54:49 +01:00
INSTALL.md docs: Reformat INSTALL.md as Markdown 2022-05-11 13:02:55 +01:00
meson_options.txt build: Add runtime_dir option to set runstatedir path 2022-12-02 21:48:03 +00:00
meson.build build: Add runtime_dir option to set runstatedir path 2022-12-02 21:48:03 +00:00
msvc_recommended_pragmas.h msvc_recommended_pragmas.h: Refine for clang-cl 2021-03-30 16:45:07 +08:00
NEWS gdbusaddress: Use runstatedir rather than localstatedir 2022-12-02 21:53:18 +00:00
README.md docs: Move INSTALL.in to INSTALL.md 2022-05-11 13:02:49 +01:00
README.win32.md README.win32.md: Mention about Window 8+ SDK requirement 2021-02-28 11:04:29 +02:00
SECURITY.md docs: Update SECURITY to stop mentioning a deprecated mailing list 2022-12-13 19:16:35 +00:00

README.md

GLib

GLib is the low-level core library that forms the basis for projects such as GTK and GNOME. It provides data structure handling for C, portability wrappers, and interfaces for such runtime functionality as an event loop, threads, dynamic loading, and an object system.

The official download locations are: https://download.gnome.org/sources/glib

The official web site is: https://www.gtk.org/

Installation

See the file 'INSTALL.md'

Supported versions

Only the most recent unstable and stable release series are supported. All older versions are not supported upstream and may contain bugs, some of which may be exploitable security vulnerabilities.

See SECURITY.md for more details.

Documentation

API documentation is available online for GLib for the:

Discussion

If you have a question about how to use GLib, seek help on GNOME’s Discourse instance. Alternatively, ask a question on StackOverflow and tag it glib.

Reporting bugs

Bugs should be reported to the GNOME issue tracking system. You will need to create an account for yourself. You may also submit bugs by e-mail (without an account) by e-mailing incoming+gnome-glib-658-issue-@gitlab.gnome.org, but this will give you a degraded experience.

Bugs are for reporting problems in GLib itself, not for asking questions about how to use it. To ask questions, use one of our discussion forums.

In bug reports please include:

  • Information about your system. For instance:
    • What operating system and version
    • For Linux, what version of the C library
    • And anything else you think is relevant.
  • How to reproduce the bug.
    • If you can reproduce it with one of the test programs that are built in the tests/ subdirectory, that will be most convenient. Otherwise, please include a short test program that exhibits the behavior. As a last resort, you can also provide a pointer to a larger piece of software that can be downloaded.
  • If the bug was a crash, the exact text that was printed out when the crash occurred.
  • Further information such as stack traces may be useful, but is not necessary.

Contributing to GLib

Please follow the contribution guide to know how to start contributing to GLib.

Patches should be submitted as merge requests to gitlab.gnome.org. If the patch fixes an existing issue, please refer to the issue in your commit message with the following notation (for issue 123):

Closes: #123

Otherwise, create a new merge request that introduces the change. Filing a separate issue is not required.

Default branch renamed to main

The default development branch of GLib has been renamed to main. To update your local checkout, use:

git checkout master
git branch -m master main
git fetch
git branch --unset-upstream
git branch -u origin/main
git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main