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This makes the G_DEFINE_TYPE(), G_DEFINE_INTERFACE() and similar variants provide a TypeName##_type_id global simimlar to how the private offset is stored as a global. What this allows for, is for applications and libraries which have high demand on the type system to have an escape hatch to improve performance. It has been observed that most of the type checking comes from inside the same module that implements the type. Therefore, if that source file can access the GType without an external call to the get_type() function, the overhead can be reduced to an address load. For example, this is used in libdex heavily to ensure that get_type() do not show up in performance profiles. This is done by redefining the type macro to use the global variable. #undef FOO_TYPE_BAR #define FOO_TYPE_BAR FooBar_type_id The one place where you need to be careful of this is the new function which may cause the registration of the type if global registration at library/application startup is not performed. Additionally, if using new-style G_DECLARE_* macros, you may also want to override the IS_TYPE() macro to use the fast path. #define FOO_IS_BAR(obj) G_TYPE_CHECK_INSTANCE_TYPE(obj, FOO_TYPE_BAR) On this system, this can have a wild performance implication. For example, the type check for GDBusMessage when dragging a window around in GNOME Shell and activating the overview had a whopping 2.96% of samples.
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’. There is separate and more in-depth documentation for building GLib on Windows.
Supported versions
Upstream GLib only supports the most recent stable release series, the previous stable release series, and the current development release series. 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 you can reproduce it with one of the test programs that are built
in the
- 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. Note that you will need to be logged in to the site to use this page. 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.