3 GLib is the low-level core library that forms the basis for projects such
4 as GTK and GNOME. It provides data structure handling for C, portability
5 wrappers, and interfaces for such runtime functionality as an event loop,
6 threads, dynamic loading, and an object system.
8 The official download locations are:
9 <https://download.gnome.org/sources/glib>
11 The official web site is:
12 <https://www.gtk.org/>
16 See the file '[INSTALL.in](INSTALL.in)'
20 Bugs should be reported to the GNOME issue tracking system.
21 (<https://gitlab.gnome.org/GNOME/glib/issues/new>). You will need
22 to create an account for yourself.
24 In the bug report please include:
26 * Information about your system. For instance:
27 * What operating system and version
28 * For Linux, what version of the C library
29 * And anything else you think is relevant.
30 * How to reproduce the bug.
31 * If you can reproduce it with one of the test programs that are built
32 in the tests/ subdirectory, that will be most convenient. Otherwise,
33 please include a short test program that exhibits the behavior.
34 As a last resort, you can also provide a pointer to a larger piece
35 of software that can be downloaded.
36 * If the bug was a crash, the exact text that was printed out
37 when the crash occured.
38 * Further information such as stack traces may be useful, but
43 Patches should also be submitted as merge requests to gitlab.gnome.org. If the
44 patch fixes an existing issue, please refer to the issue in your commit message
45 with the following notation (for issue 123):
48 Otherwise, create a new merge request that introduces the change, filing a
49 separate issue is not required.
53 ### Notes about GLib 2.48
55 * The system copy of PCRE is now used by default to implement GRegex.
56 Configure with --with-pcre=internal if a system PCRE version
57 is unavailable or undesired.
59 ### Notes about GLib 2.46
61 * GTask no longer imposes a fixed limit on the number of tasks that
62 can be run_in_thread() simultaneously, since doing this inevitably
63 results in deadlocks in some use cases. Instead, it now has a base
64 number of threads that can be used "for free", but will gradually
65 add more threads to the pool if too much time passes without any
68 The exact behavior may continue to change in the future, and it's
69 possible that some future version of GLib may not do any
70 rate-limiting at all. As a result, you should no longer assume that
71 GTask will rate-limit tasks itself (or, by extension, that calls to
72 certain async gio methods will automatically be rate-limited for
73 you). If you have a very large number of tasks to run, and don't
74 want them to all run at once, you should rate-limit them yourself.
76 ### Notes about GLib 2.40
78 * g_test_run() no longer runs tests in exactly the order they are
79 registered; instead, it groups them according to test suites (ie,
80 path components) like the documentation always claimed it did. In
81 some cases, this can result in a sub-optimal ordering of tests,
82 relative to the old behavior. The fix is to change the test paths to
83 properly group together the tests that should run together. (eg, if
84 you want to run test_foo_simple(), test_bar_simple(), and
85 test_foo_using_bar() in that order, they should have test paths like
86 "/simple/foo", "/simple/bar", "/complex/foo-using-bar", not
87 "/foo/simple", "/bar/simple", "/foo/using-bar" (which would result
88 in test_foo_using_bar() running before test_bar_simple()).
90 (The behavior actually changed in GLib 2.36, but it was not
91 documented at the time, since we didn't realize it mattered.)
93 ### Notes about GLib 2.36
95 * It is no longer necessary to call g_type_init(). If you are
96 loading GLib as a dynamic module, you should be careful to avoid
97 unloading it, then subsequently loading it again. This never
98 really worked before, but it is now explicitly undefined behavior.
99 Note that if g_type_init() was the only explicit use of a GObject
100 API and you are using linker flags such as --no-add-needed, then
101 you may have to artificially use some GObject call to keep the
102 linker from optimizing away -lgobject. We recommend to use
103 g_type_ensure (G_TYPE_OBJECT) for this purpose.
105 * This release contains an incompatible change to the g_get_home_dir()
106 function. Previously, this function would effectively ignore the HOME
107 environment variable and always return the value from /etc/password.
108 As of this version, the HOME variable is used if it is set and the
109 value from /etc/passwd is only used as a fallback.
111 * The 'flowinfo' and 'scope_id' fields of GInetSocketAddress
112 (introduced in GLib 2.32) have been fixed to be in host byte order
113 rather than network byte order. This is an incompatible change, but
114 the previous behavior was clearly broken, so it seems unlikely that
117 ### Notes about GLib 2.34
119 * GIO now looks for thumbnails in XDG_CACHE_HOME, following a
120 recent alignment of the thumbnail spec with the basedir spec.
122 * The default values for GThreadPools max_unused_threads and
123 max_idle_time settings have been changed to 2 and 15*1000,
126 ### Notes about GLib 2.32
128 * It is no longer necessary to use g_thread_init() or to link against
129 libgthread. libglib is now always thread-enabled. Custom thread
130 system implementations are no longer supported (including errorcheck
133 * The thread and synchronisation APIs have been updated.
134 GMutex and GCond can be statically allocated without explicit
135 initialisation, as can new types GRWLock and GRecMutex. The
136 GStatic_______ variants of these types have been deprecated. GPrivate
137 can also be statically allocated and has a nicer API (deprecating
138 GStaticPrivate). Finally, g_thread_create() has been replaced with a
139 substantially simplified g_thread_new().
141 * The g_once_init_enter()/_leave() functions have been replaced with
142 macros that allow for a pointer to any gsize-sized object, not just a
143 gsize*. The assertions to ensure that a pointer to a correctly-sized
144 object is being used will not work with generic pointers (ie: (void*)
145 and (gpointer) casts) which would have worked with the old version.
147 * It is now mandatory to include glib.h instead of individual headers.
149 * The -uninstalled variants of the pkg-config files have been dropped.
151 * For a long time, gobject-2.0.pc mistakenly declared a public
152 dependency on gthread-2.0.pc (when the dependency should have been
153 private). This means that programs got away with calling
154 g_thread_init() without explicitly listing gthread-2.0.pc among their
157 gthread has now been removed as a gobject dependency, which will cause
158 such programs to break.
160 The fix for this problem is either to declare an explicit dependency
161 on gthread-2.0.pc (if you care about compatibility with older GLib
162 versions) or to stop calling g_thread_init().
164 * g_debug() output is no longer enabled by default. It can be enabled
165 on a per-domain basis with the G_MESSAGES_DEBUG environment variable
167 G_MESSAGES_DEBUG=domain1,domain2
171 ### Notes about GLib 2.30
173 * GObject includes a generic marshaller, g_cclosure_marshal_generic.
174 To use it, simply specify NULL as the marshaller in g_signal_new().
175 The generic marshaller is implemented with libffi, and consequently
176 GObject depends on libffi now.
178 ### Notes about GLib 2.28
180 * The GApplication API has changed compared to the version that was
181 included in the 2.25 development snapshots. Existing users will need
184 ### Notes about GLib 2.26
186 * Nothing noteworthy.
188 ### Notes about GLib 2.24
190 * It is now allowed to call g_thread_init(NULL) multiple times, and
191 to call glib functions before g_thread_init(NULL) is called
192 (although the later is mainly a change in docs as this worked before
193 too). See the GThread reference documentation for the details.
195 * GObject now links to GThread and threads are enabled automatically
196 when g_type_init() is called.
198 * GObject no longer allows to call g_object_set() on construct-only properties
199 while an object is being initialized. If this behavior is needed, setting a
200 custom constructor that just chains up will re-enable this functionality.
202 * GMappedFile on an empty file now returns NULL for the contents instead of
203 returning an empty string. The documentation specifically states that code
204 may not rely on nul-termination here so any breakage caused by this change
205 is a bug in application code.
207 ### Notes about GLib 2.22
209 * Repeated calls to g_simple_async_result_set_op_res_gpointer used
210 to leak the data. This has been fixed to always call the provided
213 ### Notes about GLib 2.20
215 * The functions for launching applications (e.g. g_app_info_launch() +
216 friends) now passes a FUSE file:// URI if possible (requires gvfs
217 with the FUSE daemon to be running and operational). With gvfs 2.26,
218 FUSE file:// URIs will be mapped back to gio URIs in the GFile
219 constructors. The intent of this change is to better integrate
220 POSIX-only applications, see bug #528670 for the rationale. The
221 only user-visible change is when an application needs to examine an
222 URI passed to it (e.g. as a positional parameter). Instead of
223 looking at the given URI, the application will now need to look at
224 the result of g_file_get_uri() after having constructed a GFile
225 object with the given URI.
227 ### Notes about GLib 2.18
229 * The recommended way of using GLib has always been to only include the
230 toplevel headers glib.h, glib-object.h and gio.h. GLib enforces this by
231 generating an error when individual headers are directly included.
232 To help with the transition, the enforcement is not turned on by
233 default for GLib headers (it is turned on for GObject and GIO).
234 To turn it on, define the preprocessor symbol G_DISABLE_SINGLE_INCLUDES.
236 ### Notes about GLib 2.16
238 * GLib now includes GIO, which adds optional dependencies against libattr
239 and libselinux for extended attribute and SELinux support. Use
240 --disable-xattr and --disable-selinux to build without these.
242 ### Notes about GLib 2.10
244 * The functions g_snprintf() and g_vsnprintf() have been removed from
245 the gprintf.h header, since they are already declared in glib.h. This
246 doesn't break documented use of gprintf.h, but people have been known
247 to include gprintf.h without including glib.h.
249 * The Unicode support has been updated to Unicode 4.1. This adds several
250 new members to the GUnicodeBreakType enumeration.
252 * The support for Solaris threads has been retired. Solaris has provided
253 POSIX threads for long enough now to have them available on every
256 * 'make check' has been changed to validate translations by calling
257 msgfmt with the -c option. As a result, it may fail on systems with
258 older gettext implementations (GNU gettext < 0.14.1, or Solaris gettext).
259 'make check' will also fail on systems where the C compiler does not
260 support ELF visibility attributes.
262 * The GMemChunk API has been deprecated in favour of a new 'slice
263 allocator'. See the g_slice documentation for more details.
265 * A new type, GInitiallyUnowned, has been introduced, which is
266 intended to serve as a common implementation of the 'floating reference'
267 concept that is e.g. used by GtkObject. Note that changing the
268 inheritance hierarchy of a type can cause problems for language
269 bindings and other code which needs to work closely with the type
270 system. Therefore, switching to GInitiallyUnowned should be done
271 carefully. g_object_compat_control() has been added to GLib 2.8.5
272 to help with the transition.
274 ### Notes about GLib 2.6.0
276 * GLib 2.6 introduces the concept of 'GLib filename encoding', which is the
277 on-disk encoding on Unix, but UTF-8 on Windows. All GLib functions
278 returning or accepting pathnames have been changed to expect
279 filenames in this encoding, and the common POSIX functions dealing
280 with pathnames have been wrapped. These wrappers are declared in the
281 header <glib/gstdio.h> which must be included explicitly; it is not
282 included through <glib.h>.
284 On current (NT-based) Windows versions, where the on-disk file names
285 are Unicode, these wrappers use the wide-character API in the C
286 library. Thus applications can handle file names containing any
287 Unicode characters through GLib's own API and its POSIX wrappers,
288 not just file names restricted to characters in the system codepage.
290 To keep binary compatibility with applications compiled against
291 older versions of GLib, the Windows DLL still provides entry points
292 with the old semantics using the old names, and applications
293 compiled against GLib 2.6 will actually use new names for the
294 functions. This is transparent to the programmer.
296 When compiling against GLib 2.6, applications intended to be
297 portable to Windows must take the UTF-8 file name encoding into
298 consideration, and use the gstdio wrappers to access files whose
299 names have been constructed from strings returned from GLib.
301 * Likewise, g_get_user_name() and g_get_real_name() have been changed
302 to return UTF-8 on Windows, while keeping the old semantics for
303 applications compiled against older versions of GLib.
305 * The GLib uses an '_' prefix to indicate private symbols that
306 must not be used by applications. On some platforms, symbols beginning
307 with prefixes such as _g will be exported from the library, on others not.
308 In no case can applications use these private symbols. In addition to that,
309 GLib+ 2.6 makes several symbols private which were not in any installed
310 header files and were never intended to be exported.
312 * To reduce code size and improve efficiency, GLib, when compiled
313 with the GNU toolchain, has separate internal and external entry
314 points for exported functions. The internal names, which begin with
315 IA__, may be seen when debugging a GLib program.
317 * On Windows, GLib no longer opens a console window when printing
318 warning messages if stdout or stderr are invalid, as they are in
319 "Windows subsystem" (GUI) applications. Simply redirect stdout or
320 stderr if you need to see them.
322 * The child watch functionality tends to reveal a bug in many
323 thread implementations (in particular the older LinuxThreads
324 implementation on Linux) where it's not possible to call waitpid()
325 for a child created in a different thread. For this reason, for
326 maximum portability, you should structure your code to fork all
327 child processes that you want to wait for from the main thread.
329 * A problem was recently discovered with g_signal_connect_object();
330 it doesn't actually disconnect the signal handler once the object being
331 connected to dies, just disables it. See the API docs for the function
332 for further details and the correct workaround that will continue to
333 work with future versions of GLib.