glfw/README.md
Camilla Löwy cd22e28495 X11: Fix empty event race condition with a pipe
There is a seemingly unavoidable race condition when waiting for data on
the X11 display connection, as long as any other thread is also making
Xlib calls.  The event data we are waiting for could be read by the
other thread as part of looking for the reply to its request, before our
poll has begun.

This commit replaces the X11 event sent by glfwPostEmptyEvent with
writing to an unnamed pipe.  The race condition remains if other Xlib
calls are made on other threads, but glfwPostEmptyEvent should now be
race-free.

This commit is based on work by pcwalton, OlivierSohn, kovidgoyal and
joaodasilva.

Closes #2033
Related to #379
Related to #1281
Related to #1285
2022-03-03 22:16:59 +01:00

334 lines
17 KiB
Markdown

# GLFW
[![Build status](https://github.com/glfw/glfw/actions/workflows/build.yml/badge.svg)](https://github.com/glfw/glfw/actions)
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## Introduction
GLFW is an Open Source, multi-platform library for OpenGL, OpenGL ES and Vulkan
application development. It provides a simple, platform-independent API for
creating windows, contexts and surfaces, reading input, handling events, etc.
GLFW natively supports Windows, macOS and Linux and other Unix-like systems. On
Linux both X11 and Wayland are supported.
GLFW is licensed under the [zlib/libpng
license](https://www.glfw.org/license.html).
You can [download](https://www.glfw.org/download.html) the latest stable release
as source or Windows binaries, or fetch the `latest` branch from GitHub. Each
release starting with 3.0 also has a corresponding [annotated
tag](https://github.com/glfw/glfw/releases) with source and binary archives.
The [documentation](https://www.glfw.org/docs/latest/) is available online and is
included in all source and binary archives. See the [release
notes](https://www.glfw.org/docs/latest/news.html) for new features, caveats and
deprecations in the latest release. For more details see the [version
history](https://www.glfw.org/changelog.html).
The `master` branch is the stable integration branch and _should_ always compile
and run on all supported platforms, although details of newly added features may
change until they have been included in a release. New features and many bug
fixes live in [other branches](https://github.com/glfw/glfw/branches/all) until
they are stable enough to merge.
If you are new to GLFW, you may find the
[tutorial](https://www.glfw.org/docs/latest/quick.html) for GLFW 3 useful. If
you have used GLFW 2 in the past, there is a [transition
guide](https://www.glfw.org/docs/latest/moving.html) for moving to the GLFW
3 API.
GLFW exists because of the contributions of [many people](CONTRIBUTORS.md)
around the world, whether by reporting bugs, providing community support, adding
features, reviewing or testing code, debugging, proofreading docs, suggesting
features or fixing bugs.
## Compiling GLFW
GLFW itself requires only the headers and libraries for your OS and window
system. It does not need the headers for any context creation API (WGL, GLX,
EGL, NSGL, OSMesa) or rendering API (OpenGL, OpenGL ES, Vulkan) to enable
support for them.
GLFW supports compilation on Windows with Visual C++ 2010 and later, MinGW and
MinGW-w64, on macOS with Clang and on Linux and other Unix-like systems with GCC
and Clang. It will likely compile in other environments as well, but this is
not regularly tested.
There are [pre-compiled Windows binaries](https://www.glfw.org/download.html)
available for all supported compilers.
See the [compilation guide](https://www.glfw.org/docs/latest/compile.html) for
more information about how to compile GLFW yourself.
## Using GLFW
See the [documentation](https://www.glfw.org/docs/latest/) for tutorials, guides
and the API reference.
## Contributing to GLFW
See the [contribution
guide](https://github.com/glfw/glfw/blob/master/docs/CONTRIBUTING.md) for
more information.
## System requirements
GLFW supports Windows XP and later and macOS 10.8 and later. Linux and other
Unix-like systems running the X Window System are supported even without
a desktop environment or modern extensions, although some features require
a running window or clipboard manager. The OSMesa backend requires Mesa 6.3.
See the [compatibility guide](https://www.glfw.org/docs/latest/compat.html)
in the documentation for more information.
## Dependencies
GLFW itself needs only CMake 3.1 or later and the headers and libraries for your
OS and window system.
The examples and test programs depend on a number of tiny libraries. These are
located in the `deps/` directory.
- [getopt\_port](https://github.com/kimgr/getopt_port/) for examples
with command-line options
- [TinyCThread](https://github.com/tinycthread/tinycthread) for threaded
examples
- [glad2](https://github.com/Dav1dde/glad) for loading OpenGL and Vulkan
functions
- [linmath.h](https://github.com/datenwolf/linmath.h) for linear algebra in
examples
- [Nuklear](https://github.com/Immediate-Mode-UI/Nuklear) for test and example UI
- [stb\_image\_write](https://github.com/nothings/stb) for writing images to disk
The documentation is generated with [Doxygen](https://doxygen.org/) if CMake can
find that tool.
## Reporting bugs
Bugs are reported to our [issue tracker](https://github.com/glfw/glfw/issues).
Please check the [contribution
guide](https://github.com/glfw/glfw/blob/master/docs/CONTRIBUTING.md) for
information on what to include when reporting a bug.
## Changelog
- Added `GLFW_PLATFORM` init hint for runtime platform selection (#1958)
- Added `GLFW_ANY_PLATFORM`, `GLFW_PLATFORM_WIN32`, `GLFW_PLATFORM_COCOA`,
`GLFW_PLATFORM_WAYLAND`, `GLFW_PLATFORM_X11` and `GLFW_PLATFORM_NULL` symbols to
specify the desired platform (#1958)
- Added `glfwGetPlatform` function to query what platform was selected (#1655,#1958)
- Added `glfwPlatformSupported` function to query if a platform is supported
(#1655,#1958)
- Added `glfwInitAllocator` for setting a custom memory allocator (#544,#1628,#1947)
- Added `GLFWallocator` struct and `GLFWallocatefun`, `GLFWreallocatefun` and
`GLFWdeallocatefun` types (#544,#1628,#1947)
- Added `glfwInitVulkanLoader` for using a non-default Vulkan loader (#1374,#1890)
- Added `GLFW_RESIZE_NWSE_CURSOR`, `GLFW_RESIZE_NESW_CURSOR`,
`GLFW_RESIZE_ALL_CURSOR` and `GLFW_NOT_ALLOWED_CURSOR` cursor shapes (#427)
- Added `GLFW_RESIZE_EW_CURSOR` alias for `GLFW_HRESIZE_CURSOR` (#427)
- Added `GLFW_RESIZE_NS_CURSOR` alias for `GLFW_VRESIZE_CURSOR` (#427)
- Added `GLFW_POINTING_HAND_CURSOR` alias for `GLFW_HAND_CURSOR` (#427)
- Added `GLFW_MOUSE_PASSTHROUGH` window hint for letting mouse input pass
through the window (#1236,#1568)
- Added `GLFW_PLATFORM_UNAVAILABLE` error for platform detection failures (#1958)
- Added `GLFW_FEATURE_UNAVAILABLE` error for platform limitations (#1692)
- Added `GLFW_FEATURE_UNIMPLEMENTED` error for incomplete backends (#1692)
- Added `GLFW_ANGLE_PLATFORM_TYPE` init hint and `GLFW_ANGLE_PLATFORM_TYPE_*`
values to select ANGLE backend (#1380)
- Added `GLFW_X11_XCB_VULKAN_SURFACE` init hint for selecting X11 Vulkan
surface extension (#1793)
- Added `GLFW_BUILD_WIN32` CMake option for enabling Win32 support (#1958)
- Added `GLFW_BUILD_COCOA` CMake option for enabling Cocoa support (#1958)
- Added `GLFW_BUILD_X11` CMake option for enabling X11 support (#1958)
- Added `GLFW_LIBRARY_TYPE` CMake variable for overriding the library type
(#279,#1307,#1497,#1574,#1928)
- Added `GLFW_PKG_CONFIG_REQUIRES_PRIVATE` and `GLFW_PKG_CONFIG_LIBS_PRIVATE` CMake
variables exposing pkg-config dependencies (#1307)
- Made joystick subsystem initialize at first use (#1284,#1646)
- Made `GLFW_DOUBLEBUFFER` a read-only window attribute
- Updated the minimum required CMake version to 3.1
- Updated gamepad mappings from upstream
- Disabled tests and examples by default when built as a CMake subdirectory
- Renamed `GLFW_USE_WAYLAND` CMake option to `GLFW_BUILD_WAYLAND` (#1958)
- Removed `GLFW_USE_OSMESA` CMake option enabling the Null platform (#1958)
- Removed CMake generated configuration header
- Bugfix: The CMake config-file package used an absolute path and was not
relocatable (#1470)
- Bugfix: Video modes with a duplicate screen area were discarded (#1555,#1556)
- Bugfix: Compiling with -Wextra-semi caused warnings (#1440)
- Bugfix: Built-in mappings failed because some OEMs re-used VID/PID (#1583)
- Bugfix: Some extension loader headers did not prevent default OpenGL header
inclusion (#1695)
- Bugfix: Buffers were swapped at creation on single-buffered windows (#1873)
- Bugfix: Gamepad mapping updates could spam `GLFW_INVALID_VALUE` due to
incompatible controllers sharing hardware ID (#1763)
- Bugfix: Native access functions for context handles did not check that the API matched
- [Win32] Added the `GLFW_WIN32_KEYBOARD_MENU` window hint for enabling access
to the window menu
- [Win32] Added a version info resource to the GLFW DLL
- [Win32] Disabled framebuffer transparency on Windows 7 when DWM windows are
opaque (#1512)
- [Win32] Bugfix: `GLFW_INCLUDE_VULKAN` plus `VK_USE_PLATFORM_WIN32_KHR` caused
symbol redefinition (#1524)
- [Win32] Bugfix: The cursor position event was emitted before its cursor enter
event (#1490)
- [Win32] Bugfix: The window hint `GLFW_MAXIMIZED` did not move or resize the
window (#1499)
- [Win32] Bugfix: Disabled cursor mode interfered with some non-client actions
- [Win32] Bugfix: Super key was not released after Win+V hotkey (#1622)
- [Win32] Bugfix: `glfwGetKeyName` could access out of bounds and return an
invalid pointer
- [Win32] Bugfix: Some synthetic key events were reported as `GLFW_KEY_UNKNOWN`
(#1623)
- [Win32] Bugfix: Non-BMP Unicode codepoint input was reported as UTF-16
- [Win32] Bugfix: Monitor functions could return invalid values after
configuration change (#1761)
- [Win32] Bugfix: Initialization would segfault on Windows 8 (not 8.1) (#1775)
- [Win32] Bugfix: Duplicate size events were not filtered (#1610)
- [Win32] Bugfix: Full screen windows were incorrectly resized by DPI changes
(#1582)
- [Win32] Bugfix: `GLFW_SCALE_TO_MONITOR` had no effect on systems older than
Windows 10 version 1703 (#1511)
- [Win32] Bugfix: `USE_MSVC_RUNTIME_LIBRARY_DLL` had no effect on CMake 3.15 or
later (#1783,#1796)
- [Win32] Bugfix: Compilation with LLVM for Windows failed (#1807,#1824,#1874)
- [Win32] Bugfix: The foreground lock timeout was overridden, ignoring the user
- [Win32] Bugfix: Content scale queries could fail silently (#1615)
- [Win32] Bugfix: Content scales could have garbage values if monitor was recently
disconnected (#1615)
- [Win32] Bugfix: Key name update modified global key state on Windows 10 1607
and later (#2018)
- [Cocoa] Added support for `VK_EXT_metal_surface` (#1619)
- [Cocoa] Added locating the Vulkan loader at runtime in an application bundle
- [Cocoa] Moved main menu creation to GLFW initialization time (#1649)
- [Cocoa] Changed `EGLNativeWindowType` from `NSView` to `CALayer` (#1169)
- [Cocoa] Changed F13 key to report Print Screen for cross-platform consistency
(#1786)
- [Cocoa] Removed dependency on the CoreVideo framework
- [Cocoa] Bugfix: `glfwSetWindowSize` used a bottom-left anchor point (#1553)
- [Cocoa] Bugfix: Window remained on screen after destruction until event poll
(#1412)
- [Cocoa] Bugfix: Event processing before window creation would assert (#1543)
- [Cocoa] Bugfix: Undecorated windows could not be iconified on recent macOS
- [Cocoa] Bugfix: Touching event queue from secondary thread before main thread
would abort (#1649)
- [Cocoa] Bugfix: Non-BMP Unicode codepoint input was reported as UTF-16
(#1635)
- [Cocoa] Bugfix: Failing to retrieve the refresh rate of built-in displays
could leak memory
- [Cocoa] Bugfix: Objective-C files were compiled as C with CMake 3.19 (#1787)
- [Cocoa] Bugfix: Duplicate video modes were not filtered out (#1830)
- [Cocoa] Bugfix: Menu bar was not clickable on macOS 10.15+ until it lost and
regained focus (#1648,#1802)
- [Cocoa] Bugfix: Monitor name query could segfault on macOS 11 (#1809,#1833)
- [Cocoa] Bugfix: The install name of the installed dylib was relative (#1504)
- [Cocoa] Bugfix: The MoltenVK layer contents scale was updated only after
related events were emitted
- [Cocoa] Bugfix: Moving the cursor programmatically would freeze it for
a fraction of a second (#1962)
- [Cocoa] Bugfix: `kIOMasterPortDefault` was deprecated in macOS 12.0 (#1980)
- [Cocoa] Bugfix: `kUTTypeURL` was deprecated in macOS 12.0 (#2003)
- [X11] Bugfix: The CMake files did not check for the XInput headers (#1480)
- [X11] Bugfix: Key names were not updated when the keyboard layout changed
(#1462,#1528)
- [X11] Bugfix: Decorations could not be enabled after window creation (#1566)
- [X11] Bugfix: Content scale fallback value could be inconsistent (#1578)
- [X11] Bugfix: `glfwMaximizeWindow` had no effect on hidden windows
- [X11] Bugfix: Clearing `GLFW_FLOATING` on a hidden window caused invalid read
- [X11] Bugfix: Changing `GLFW_FLOATING` on a hidden window could silently fail
- [X11] Bugfix: Disabled cursor mode was interrupted by indicator windows
- [X11] Bugfix: Monitor physical dimensions could be reported as zero mm
- [X11] Bugfix: Window position events were not emitted during resizing (#1613)
- [X11] Bugfix: `glfwFocusWindow` could terminate on older WMs or without a WM
- [X11] Bugfix: Querying a disconnected monitor could segfault (#1602)
- [X11] Bugfix: IME input of CJK was broken for "C" locale (#1587,#1636)
- [X11] Bugfix: Termination would segfault if the IM had been destroyed
- [X11] Bugfix: Any IM started after initialization would not be detected
- [X11] Bugfix: Xlib errors caused by other parts of the application could be
reported as GLFW errors
- [X11] Bugfix: A handle race condition could cause a `BadWindow` error (#1633)
- [X11] Bugfix: XKB path used keysyms instead of physical locations for
non-printable keys (#1598)
- [X11] Bugfix: Function keys were mapped to `GLFW_KEY_UNKNOWN` for some layout
combinations (#1598)
- [X11] Bugfix: Keys pressed simultaneously with others were not always
reported (#1112,#1415,#1472,#1616)
- [X11] Bugfix: Some window attributes were not applied on leaving fullscreen
(#1863)
- [X11] Bugfix: Changing `GLFW_FLOATING` could leak memory
- [X11] Bugfix: Icon pixel format conversion worked only by accident, relying on
undefined behavior (#1986)
- [X11] Bugfix: Dynamic loading on OpenBSD failed due to soname differences
- [X11] Bugfix: Waiting for events would fail if file descriptor was too large
(#2024)
- [X11] Bugfix: Joystick events could lead to busy-waiting (#1872)
- [X11] Bugfix: `glfwWaitEvents*` did not continue for joystick events
- [X11] Bugfix: `glfwPostEmptyEvent` could be ignored due to race condition
(#379,#1281,#1285,#2033)
- [Wayland] Added dynamic loading of all Wayland libraries
- [Wayland] Added support for key names via xkbcommon
- [Wayland] Removed support for `wl_shell` (#1443)
- [Wayland] Bugfix: The `GLFW_HAND_CURSOR` shape used the wrong image (#1432)
- [Wayland] Bugfix: `CLOCK_MONOTONIC` was not correctly enabled
- [Wayland] Bugfix: Repeated keys could be reported with `NULL` window (#1704)
- [Wayland] Bugfix: Retrieving partial framebuffer size would segfault
- [Wayland] Bugfix: Scrolling offsets were inverted compared to other platforms
(#1463)
- [Wayland] Bugfix: Client-Side Decorations were destroyed in the wrong order
(#1798)
- [Wayland] Bugfix: Monitors physical size could report zero (#1784,#1792)
- [Wayland] Bugfix: Some keys were not repeating in Wayland (#1908)
- [Wayland] Bugfix: Non-arrow cursors are offset from the hotspot (#1706,#1899)
- [Wayland] Bugfix: The `O_CLOEXEC` flag was not defined on FreeBSD
- [Wayland] Bugfix: Key repeat could lead to a race condition (#1710)
- [Wayland] Bugfix: Activating a window would emit two input focus events
- [Wayland] Bugfix: Disable key repeat mechanism when window loses input focus
- [Wayland] Bugfix: Window hiding and showing did not work (#1492,#1731)
- [Wayland] Bugfix: A key being repeated was not released when window lost focus
- [Wayland] Bugfix: Showing a hidden window did not emit a window refresh event
- [Wayland] Bugfix: Full screen window creation did not ignore `GLFW_VISIBLE`
- [Wayland] Bugfix: Some keys were reported as wrong key or `GLFW_KEY_UNKNOWN`
- [Wayland] Bugfix: Text input did not repeat along with key repeat
- [POSIX] Removed use of deprecated function `gettimeofday`
- [POSIX] Bugfix: `CLOCK_MONOTONIC` was not correctly tested for or enabled
- [WGL] Disabled the DWM swap interval hack for Windows 8 and later (#1072)
- [NSGL] Removed enforcement of forward-compatible flag for core contexts
- [NSGL] Bugfix: `GLFW_COCOA_RETINA_FRAMEBUFFER` had no effect on newer
macOS versions (#1442)
- [NSGL] Bugfix: Workaround for swap interval on 10.14 broke on 10.12 (#1483)
- [NSGL] Bugfix: Defining `GL_SILENCE_DEPRECATION` externally caused
a duplicate definition warning (#1840)
- [EGL] Added platform selection via the `EGL_EXT_platform_base` extension
(#442)
- [EGL] Added ANGLE backend selection via `EGL_ANGLE_platform_angle` extension
(#1380)
- [EGL] Bugfix: The `GLFW_DOUBLEBUFFER` context attribute was ignored (#1843)
- [GLX] Bugfix: Context creation failed if GLX 1.4 was not exported by GLX library
## Contact
On [glfw.org](https://www.glfw.org/) you can find the latest version of GLFW, as
well as news, documentation and other information about the project.
If you have questions related to the use of GLFW, we have a
[forum](https://discourse.glfw.org/), and the `#glfw` IRC channel on
[Libera.Chat](https://libera.chat/).
If you have a bug to report, a patch to submit or a feature you'd like to
request, please file it in the
[issue tracker](https://github.com/glfw/glfw/issues) on GitHub.
Finally, if you're interested in helping out with the development of GLFW or
porting it to your favorite platform, join us on the forum, GitHub or IRC.