docs/compat.dox - third_party/glfw - Git at Google

 /*!

 @page compat_guide Standards conformance

 @tableofcontents

 This guide describes the various API extensions used by this version of GLFW.
 It lists what are essentially implementation details, but which are nonetheless
 vital knowledge for developers intending to deploy their applications on a wide
 range of machines.

 The information in this guide is not a part of GLFW API, but merely
 preconditions for some parts of the library to function on a given machine.  Any
 part of this information may change in future versions of GLFW and that will not
 be considered a breaking API change.


 @section compat_x11 X11 extensions, protocols and IPC standards

 As GLFW uses Xlib directly, without any intervening toolkit
 library, it has sole responsibility for interacting well with the many and
 varied window managers in use on Unix-like systems.  In order for applications
 and window managers to work well together, a number of standards and
 conventions have been developed that regulate behavior outside the scope of the
 X11 API; most importantly the
 [Inter-Client Communication Conventions Manual](https://www.tronche.com/gui/x/icccm/)
 (ICCCM) and
 [Extended Window Manager Hints](https://standards.freedesktop.org/wm-spec/wm-spec-latest.html)
 (EWMH) standards.

 GLFW uses the `_MOTIF_WM_HINTS` window property to support borderless windows.
 If the running window manager does not support this property, the
 `GLFW_DECORATED` hint will have no effect.

 GLFW uses the ICCCM `WM_DELETE_WINDOW` protocol to intercept the user
 attempting to close the GLFW window.  If the running window manager does not
 support this protocol, the close callback will never be called.

 GLFW uses the EWMH `_NET_WM_PING` protocol, allowing the window manager notify
 the user when the application has stopped responding, i.e. when it has ceased to
 process events.  If the running window manager does not support this protocol,
 the user will not be notified if the application locks up.

 GLFW uses the EWMH `_NET_WM_STATE_FULLSCREEN` window state to tell the window
 manager to make the GLFW window full screen.  If the running window manager does
 not support this state, full screen windows may not work properly.  GLFW has
 a fallback code path in case this state is unavailable, but every window manager
 behaves slightly differently in this regard.

 GLFW uses the EWMH `_NET_WM_BYPASS_COMPOSITOR` window property to tell a
 compositing window manager to un-redirect full screen GLFW windows.  If the
 running window manager uses compositing but does not support this property then
 additional copying may be performed for each buffer swap of full screen windows.

 GLFW uses the
 [clipboard manager protocol](https://www.freedesktop.org/wiki/ClipboardManager/)
 to push a clipboard string (i.e. selection) owned by a GLFW window about to be
 destroyed to the clipboard manager.  If there is no running clipboard manager,
 the clipboard string will be unavailable once the window has been destroyed.

 GLFW uses the
 [X drag-and-drop protocol](https://www.freedesktop.org/wiki/Specifications/XDND/)
 to provide file drop events.  If the application originating the drag does not
 support this protocol, drag and drop will not work.

 GLFW uses the XRandR 1.3 extension to provide multi-monitor support.  If the
 running X server does not support this version of this extension, multi-monitor
 support will not function and only a single, desktop-spanning monitor will be
 reported.

 GLFW uses the XRandR 1.3 and Xf86vidmode extensions to provide gamma ramp
 support.  If the running X server does not support either or both of these
 extensions, gamma ramp support will not function.

 GLFW uses the Xkb extension and detectable auto-repeat to provide keyboard
 input.  If the running X server does not support this extension, a non-Xkb
 fallback path is used.

 GLFW uses the XInput2 extension to provide raw, non-accelerated mouse motion
 when the cursor is disabled.  If the running X server does not support this
 extension, regular accelerated mouse motion will be used.

 GLFW uses both the XRender extension and the compositing manager to support
 transparent window framebuffers.  If the running X server does not support this
 extension or there is no running compositing manager, the
 `GLFW_TRANSPARENT_FRAMEBUFFER` framebuffer hint will have no effect.


 @section compat_wayland Wayland protocols and IPC standards

 As GLFW uses libwayland directly, without any intervening toolkit library, it
 has sole responsibility for interacting well with every compositor in use on
 Unix-like systems.  Most of the features are provided by the core protocol,
 while cursor support is provided by the libwayland-cursor helper library, EGL
 integration by libwayland-egl, and keyboard handling by
 [libxkbcommon](https://xkbcommon.org/).  In addition, GLFW uses some protocols
 from wayland-protocols to provide additional features if the compositor
 supports them.

 GLFW uses xkbcommon 0.5.0 to provide compose key support.  When it has been
 built against an older xkbcommon, the compose key will be disabled even if it
 has been configured in the compositor.

 GLFW uses the [xdg-shell
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/stable/xdg-shell/xdg-shell.xml)
 to provide better window management.  This protocol is part of
 wayland-protocols 1.12, and mandatory at build time.  If the running compositor
 does not support this protocol, the older [wl_shell
 interface](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n972)
 will be used instead.  This will result in a worse integration with the
 desktop, especially on tiling compositors.

 GLFW uses the [relative pointer
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/relative-pointer/relative-pointer-unstable-v1.xml)
 alongside the [pointer constraints
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml)
 to implement disabled cursor.  These two protocols are part of
 wayland-protocols 1.1, and mandatory at build time.  If the running compositor
 does not support both of these protocols, disabling the cursor will have no
 effect.

 GLFW uses the [idle inhibit
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml)
 to prohibit the screensaver from starting.  This protocol is part of
 wayland-protocols 1.6, and mandatory at build time.  If the running compositor
 does not support this protocol, the screensaver may start even for full screen
 windows.

 GLFW uses the [xdg-decoration
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml)
 to request decorations to be drawn around its windows.  This protocol is part
 of wayland-protocols 1.15, and mandatory at build time.  If the running
 compositor does not support this protocol, a very simple frame will be drawn by
 GLFW itself, using the [viewporter
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/stable/viewporter/viewporter.xml)
 alongside
 [subsurfaces](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n2598).
 This protocol is part of wayland-protocols 1.4, and mandatory at build time.
 If the running compositor does not support this protocol either, no decorations
 will be drawn around windows.


 @section compat_glx GLX extensions

 The GLX API is the default API used to create OpenGL contexts on Unix-like
 systems using the X Window System.

 GLFW uses the GLX 1.3 `GLXFBConfig` functions to enumerate and select framebuffer pixel
 formats.  If GLX 1.3 is not supported, @ref glfwInit will fail.

 GLFW uses the `GLX_MESA_swap_control,` `GLX_EXT_swap_control` and
 `GLX_SGI_swap_control` extensions to provide vertical retrace synchronization
 (or _vsync_), in that order of preference.  Where none of these extension are
 available, calling @ref glfwSwapInterval will have no effect.

 GLFW uses the `GLX_ARB_multisample` extension to create contexts with
 multisampling anti-aliasing.  Where this extension is unavailable, the
 `GLFW_SAMPLES` hint will have no effect.

 GLFW uses the `GLX_ARB_create_context` extension when available, even when
 creating OpenGL contexts of version 2.1 and below.  Where this extension is
 unavailable, the `GLFW_CONTEXT_VERSION_MAJOR` and `GLFW_CONTEXT_VERSION_MINOR`
 hints will only be partially supported, the `GLFW_OPENGL_DEBUG_CONTEXT` hint
 will have no effect, and setting the `GLFW_OPENGL_PROFILE` or
 `GLFW_OPENGL_FORWARD_COMPAT` hints to `GLFW_TRUE` will cause @ref
 glfwCreateWindow to fail.

 GLFW uses the `GLX_ARB_create_context_profile` extension to provide support for
 context profiles.  Where this extension is unavailable, setting the
 `GLFW_OPENGL_PROFILE` hint to anything but `GLFW_OPENGL_ANY_PROFILE`, or setting
 `GLFW_CLIENT_API` to anything but `GLFW_OPENGL_API` or `GLFW_NO_API` will cause
 @ref glfwCreateWindow to fail.

 GLFW uses the `GLX_ARB_context_flush_control` extension to provide control over
 whether a context is flushed when it is released (made non-current).  Where this
 extension is unavailable, the `GLFW_CONTEXT_RELEASE_BEHAVIOR` hint will have no
 effect and the context will always be flushed when released.

 GLFW uses the `GLX_ARB_framebuffer_sRGB` and `GLX_EXT_framebuffer_sRGB`
 extensions to provide support for sRGB framebuffers.  Where both of these
 extensions are unavailable, the `GLFW_SRGB_CAPABLE` hint will have no effect.


 @section compat_wgl WGL extensions

 The WGL API is used to create OpenGL contexts on Microsoft Windows and other
 implementations of the Win32 API, such as Wine.

 GLFW uses either the `WGL_EXT_extension_string` or the
 `WGL_ARB_extension_string` extension to check for the presence of all other WGL
 extensions listed below.  If both are available, the EXT one is preferred.  If
 neither is available, no other extensions are used and many GLFW features
 related to context creation will have no effect or cause errors when used.

 GLFW uses the `WGL_EXT_swap_control` extension to provide vertical retrace
 synchronization (or _vsync_).  Where this extension is unavailable, calling @ref
 glfwSwapInterval will have no effect.

 GLFW uses the `WGL_ARB_pixel_format` and `WGL_ARB_multisample` extensions to
 create contexts with multisampling anti-aliasing.  Where these extensions are
 unavailable, the `GLFW_SAMPLES` hint will have no effect.

 GLFW uses the `WGL_ARB_create_context` extension when available, even when
 creating OpenGL contexts of version 2.1 and below.  Where this extension is
 unavailable, the `GLFW_CONTEXT_VERSION_MAJOR` and `GLFW_CONTEXT_VERSION_MINOR`
 hints will only be partially supported, the `GLFW_OPENGL_DEBUG_CONTEXT` hint
 will have no effect, and setting the `GLFW_OPENGL_PROFILE` or
 `GLFW_OPENGL_FORWARD_COMPAT` hints to `GLFW_TRUE` will cause @ref
 glfwCreateWindow to fail.

 GLFW uses the `WGL_ARB_create_context_profile` extension to provide support for
 context profiles.  Where this extension is unavailable, setting the
 `GLFW_OPENGL_PROFILE` hint to anything but `GLFW_OPENGL_ANY_PROFILE` will cause
 @ref glfwCreateWindow to fail.

 GLFW uses the `WGL_ARB_context_flush_control` extension to provide control over
 whether a context is flushed when it is released (made non-current).  Where this
 extension is unavailable, the `GLFW_CONTEXT_RELEASE_BEHAVIOR` hint will have no
 effect and the context will always be flushed when released.

 GLFW uses the `WGL_ARB_framebuffer_sRGB` and `WGL_EXT_framebuffer_sRGB`
 extensions to provide support for sRGB framebuffers.  Where both of these
 extension are unavailable, the `GLFW_SRGB_CAPABLE` hint will have no effect.


 @section compat_osx OpenGL on macOS

 Support for OpenGL 3.2 and above was introduced with OS X 10.7 and even then
 only forward-compatible, core profile contexts are supported.  Support for
 OpenGL 4.1 was introduced with OS X 10.9, also limited to forward-compatible,
 core profile contexts.  There is also still no mechanism for requesting debug
 contexts or no-error contexts.  Versions of Mac OS X earlier than 10.7 support
 at most OpenGL version 2.1.

 Because of this, on OS X 10.7 and later, the `GLFW_CONTEXT_VERSION_MAJOR` and
 `GLFW_CONTEXT_VERSION_MINOR` hints will cause @ref glfwCreateWindow to fail if
 given version 3.0 or 3.1.  The `GLFW_OPENGL_FORWARD_COMPAT` hint must be set to
 `GLFW_TRUE` and the `GLFW_OPENGL_PROFILE` hint must be set to
 `GLFW_OPENGL_CORE_PROFILE` when creating OpenGL 3.2 and later contexts.  The
 `GLFW_OPENGL_DEBUG_CONTEXT` and `GLFW_CONTEXT_NO_ERROR` hints are ignored.

 Also, on Mac OS X 10.6 and below, the `GLFW_CONTEXT_VERSION_MAJOR` and
 `GLFW_CONTEXT_VERSION_MINOR` hints will fail if given a version above 2.1,
 setting the `GLFW_OPENGL_PROFILE` or `GLFW_OPENGL_FORWARD_COMPAT` hints to
 a non-default value will cause @ref glfwCreateWindow to fail and the
 `GLFW_OPENGL_DEBUG_CONTEXT` hint is ignored.


 @section compat_vulkan Vulkan loader and API

 By default, GLFW uses the standard system-wide Vulkan loader to access the
 Vulkan API on all platforms except macOS.  This is installed by both graphics
 drivers and Vulkan SDKs.  If either the loader or at least one minimally
 functional ICD is missing, @ref glfwVulkanSupported will return `GLFW_FALSE` and
 all other Vulkan-related functions will fail with an @ref GLFW_API_UNAVAILABLE
 error.


 @section compat_wsi Vulkan WSI extensions

 The Vulkan WSI extensions are used to create Vulkan surfaces for GLFW windows on
 all supported platforms.

 GLFW uses the `VK_KHR_surface` and `VK_KHR_win32_surface` extensions to create
 surfaces on Microsoft Windows.  If any of these extensions are not available,
 @ref glfwGetRequiredInstanceExtensions will return an empty list and window
 surface creation will fail.

 GLFW uses the `VK_KHR_surface` and `VK_MVK_macos_surface` extensions to create
 surfaces on macOS.  If any of these extensions are not available, @ref
 glfwGetRequiredInstanceExtensions will return an empty list and window surface
 creation will fail.

 GLFW uses the `VK_KHR_surface` and either the `VK_KHR_xlib_surface` or
 `VK_KHR_xcb_surface` extensions to create surfaces on X11.  If `VK_KHR_surface`
 or both `VK_KHR_xlib_surface` and `VK_KHR_xcb_surface` are not available, @ref
 glfwGetRequiredInstanceExtensions will return an empty list and window surface
 creation will fail.

 GLFW uses the `VK_KHR_surface` and `VK_KHR_wayland_surface` extensions to create
 surfaces on Wayland.  If any of these extensions are not available, @ref
 glfwGetRequiredInstanceExtensions will return an empty list and window surface
 creation will fail.

 */
	/*!

	@page compat_guide Standards conformance

	@tableofcontents

	This guide describes the various API extensions used by this version of GLFW.
	It lists what are essentially implementation details, but which are nonetheless
	vital knowledge for developers intending to deploy their applications on a wide
	range of machines.

	The information in this guide is not a part of GLFW API, but merely
	preconditions for some parts of the library to function on a given machine. Any
	part of this information may change in future versions of GLFW and that will not
	be considered a breaking API change.


	@section compat_x11 X11 extensions, protocols and IPC standards

	As GLFW uses Xlib directly, without any intervening toolkit
	library, it has sole responsibility for interacting well with the many and
	varied window managers in use on Unix-like systems. In order for applications
	and window managers to work well together, a number of standards and
	conventions have been developed that regulate behavior outside the scope of the
	X11 API; most importantly the
	[Inter-Client Communication Conventions Manual](https://www.tronche.com/gui/x/icccm/)
	(ICCCM) and
	[Extended Window Manager Hints](https://standards.freedesktop.org/wm-spec/wm-spec-latest.html)
	(EWMH) standards.

	GLFW uses the `_MOTIF_WM_HINTS` window property to support borderless windows.
	If the running window manager does not support this property, the
	`GLFW_DECORATED` hint will have no effect.

	GLFW uses the ICCCM `WM_DELETE_WINDOW` protocol to intercept the user
	attempting to close the GLFW window. If the running window manager does not
	support this protocol, the close callback will never be called.

	GLFW uses the EWMH `_NET_WM_PING` protocol, allowing the window manager notify
	the user when the application has stopped responding, i.e. when it has ceased to
	process events. If the running window manager does not support this protocol,
	the user will not be notified if the application locks up.

	GLFW uses the EWMH `_NET_WM_STATE_FULLSCREEN` window state to tell the window
	manager to make the GLFW window full screen. If the running window manager does
	not support this state, full screen windows may not work properly. GLFW has
	a fallback code path in case this state is unavailable, but every window manager
	behaves slightly differently in this regard.

	GLFW uses the EWMH `_NET_WM_BYPASS_COMPOSITOR` window property to tell a
	compositing window manager to un-redirect full screen GLFW windows. If the
	running window manager uses compositing but does not support this property then
	additional copying may be performed for each buffer swap of full screen windows.

	GLFW uses the
	[clipboard manager protocol](https://www.freedesktop.org/wiki/ClipboardManager/)
	to push a clipboard string (i.e. selection) owned by a GLFW window about to be
	destroyed to the clipboard manager. If there is no running clipboard manager,
	the clipboard string will be unavailable once the window has been destroyed.

	GLFW uses the
	[X drag-and-drop protocol](https://www.freedesktop.org/wiki/Specifications/XDND/)
	to provide file drop events. If the application originating the drag does not
	support this protocol, drag and drop will not work.

	GLFW uses the XRandR 1.3 extension to provide multi-monitor support. If the
	running X server does not support this version of this extension, multi-monitor
	support will not function and only a single, desktop-spanning monitor will be
	reported.

	GLFW uses the XRandR 1.3 and Xf86vidmode extensions to provide gamma ramp
	support. If the running X server does not support either or both of these
	extensions, gamma ramp support will not function.

	GLFW uses the Xkb extension and detectable auto-repeat to provide keyboard
	input. If the running X server does not support this extension, a non-Xkb
	fallback path is used.

	GLFW uses the XInput2 extension to provide raw, non-accelerated mouse motion
	when the cursor is disabled. If the running X server does not support this
	extension, regular accelerated mouse motion will be used.

	GLFW uses both the XRender extension and the compositing manager to support
	transparent window framebuffers. If the running X server does not support this
	extension or there is no running compositing manager, the
	`GLFW_TRANSPARENT_FRAMEBUFFER` framebuffer hint will have no effect.


	@section compat_wayland Wayland protocols and IPC standards

	As GLFW uses libwayland directly, without any intervening toolkit library, it
	has sole responsibility for interacting well with every compositor in use on
	Unix-like systems. Most of the features are provided by the core protocol,
	while cursor support is provided by the libwayland-cursor helper library, EGL
	integration by libwayland-egl, and keyboard handling by
	[libxkbcommon](https://xkbcommon.org/). In addition, GLFW uses some protocols
	from wayland-protocols to provide additional features if the compositor
	supports them.

	GLFW uses xkbcommon 0.5.0 to provide compose key support. When it has been
	built against an older xkbcommon, the compose key will be disabled even if it
	has been configured in the compositor.

	GLFW uses the [xdg-shell
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/stable/xdg-shell/xdg-shell.xml)
	to provide better window management. This protocol is part of
	wayland-protocols 1.12, and mandatory at build time. If the running compositor
	does not support this protocol, the older [wl_shell
	interface](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n972)
	will be used instead. This will result in a worse integration with the
	desktop, especially on tiling compositors.

	GLFW uses the [relative pointer
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/relative-pointer/relative-pointer-unstable-v1.xml)
	alongside the [pointer constraints
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml)
	to implement disabled cursor. These two protocols are part of
	wayland-protocols 1.1, and mandatory at build time. If the running compositor
	does not support both of these protocols, disabling the cursor will have no
	effect.

	GLFW uses the [idle inhibit
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml)
	to prohibit the screensaver from starting. This protocol is part of
	wayland-protocols 1.6, and mandatory at build time. If the running compositor
	does not support this protocol, the screensaver may start even for full screen
	windows.

	GLFW uses the [xdg-decoration
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml)
	to request decorations to be drawn around its windows. This protocol is part
	of wayland-protocols 1.15, and mandatory at build time. If the running
	compositor does not support this protocol, a very simple frame will be drawn by
	GLFW itself, using the [viewporter
	protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/stable/viewporter/viewporter.xml)
	alongside
	[subsurfaces](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n2598).
	This protocol is part of wayland-protocols 1.4, and mandatory at build time.
	If the running compositor does not support this protocol either, no decorations
	will be drawn around windows.


	@section compat_glx GLX extensions

	The GLX API is the default API used to create OpenGL contexts on Unix-like
	systems using the X Window System.

	GLFW uses the GLX 1.3 `GLXFBConfig` functions to enumerate and select framebuffer pixel
	formats. If GLX 1.3 is not supported, @ref glfwInit will fail.

	GLFW uses the `GLX_MESA_swap_control,` `GLX_EXT_swap_control` and
	`GLX_SGI_swap_control` extensions to provide vertical retrace synchronization
	(or _vsync_), in that order of preference. Where none of these extension are
	available, calling @ref glfwSwapInterval will have no effect.

	GLFW uses the `GLX_ARB_multisample` extension to create contexts with
	multisampling anti-aliasing. Where this extension is unavailable, the
	`GLFW_SAMPLES` hint will have no effect.

	GLFW uses the `GLX_ARB_create_context` extension when available, even when
	creating OpenGL contexts of version 2.1 and below. Where this extension is
	unavailable, the `GLFW_CONTEXT_VERSION_MAJOR` and `GLFW_CONTEXT_VERSION_MINOR`
	hints will only be partially supported, the `GLFW_OPENGL_DEBUG_CONTEXT` hint
	will have no effect, and setting the `GLFW_OPENGL_PROFILE` or
	`GLFW_OPENGL_FORWARD_COMPAT` hints to `GLFW_TRUE` will cause @ref
	glfwCreateWindow to fail.

	GLFW uses the `GLX_ARB_create_context_profile` extension to provide support for
	context profiles. Where this extension is unavailable, setting the
	`GLFW_OPENGL_PROFILE` hint to anything but `GLFW_OPENGL_ANY_PROFILE`, or setting
	`GLFW_CLIENT_API` to anything but `GLFW_OPENGL_API` or `GLFW_NO_API` will cause
	@ref glfwCreateWindow to fail.

	GLFW uses the `GLX_ARB_context_flush_control` extension to provide control over
	whether a context is flushed when it is released (made non-current). Where this
	extension is unavailable, the `GLFW_CONTEXT_RELEASE_BEHAVIOR` hint will have no
	effect and the context will always be flushed when released.

	GLFW uses the `GLX_ARB_framebuffer_sRGB` and `GLX_EXT_framebuffer_sRGB`
	extensions to provide support for sRGB framebuffers. Where both of these
	extensions are unavailable, the `GLFW_SRGB_CAPABLE` hint will have no effect.


	@section compat_wgl WGL extensions

	The WGL API is used to create OpenGL contexts on Microsoft Windows and other
	implementations of the Win32 API, such as Wine.

	GLFW uses either the `WGL_EXT_extension_string` or the
	`WGL_ARB_extension_string` extension to check for the presence of all other WGL
	extensions listed below. If both are available, the EXT one is preferred. If
	neither is available, no other extensions are used and many GLFW features
	related to context creation will have no effect or cause errors when used.

	GLFW uses the `WGL_EXT_swap_control` extension to provide vertical retrace
	synchronization (or _vsync_). Where this extension is unavailable, calling @ref
	glfwSwapInterval will have no effect.

	GLFW uses the `WGL_ARB_pixel_format` and `WGL_ARB_multisample` extensions to
	create contexts with multisampling anti-aliasing. Where these extensions are
	unavailable, the `GLFW_SAMPLES` hint will have no effect.

	GLFW uses the `WGL_ARB_create_context` extension when available, even when
	creating OpenGL contexts of version 2.1 and below. Where this extension is
	unavailable, the `GLFW_CONTEXT_VERSION_MAJOR` and `GLFW_CONTEXT_VERSION_MINOR`
	hints will only be partially supported, the `GLFW_OPENGL_DEBUG_CONTEXT` hint
	will have no effect, and setting the `GLFW_OPENGL_PROFILE` or
	`GLFW_OPENGL_FORWARD_COMPAT` hints to `GLFW_TRUE` will cause @ref
	glfwCreateWindow to fail.

	GLFW uses the `WGL_ARB_create_context_profile` extension to provide support for
	context profiles. Where this extension is unavailable, setting the
	`GLFW_OPENGL_PROFILE` hint to anything but `GLFW_OPENGL_ANY_PROFILE` will cause
	@ref glfwCreateWindow to fail.

	GLFW uses the `WGL_ARB_context_flush_control` extension to provide control over
	whether a context is flushed when it is released (made non-current). Where this
	extension is unavailable, the `GLFW_CONTEXT_RELEASE_BEHAVIOR` hint will have no
	effect and the context will always be flushed when released.

	GLFW uses the `WGL_ARB_framebuffer_sRGB` and `WGL_EXT_framebuffer_sRGB`
	extensions to provide support for sRGB framebuffers. Where both of these
	extension are unavailable, the `GLFW_SRGB_CAPABLE` hint will have no effect.


	@section compat_osx OpenGL on macOS

	Support for OpenGL 3.2 and above was introduced with OS X 10.7 and even then
	only forward-compatible, core profile contexts are supported. Support for
	OpenGL 4.1 was introduced with OS X 10.9, also limited to forward-compatible,
	core profile contexts. There is also still no mechanism for requesting debug
	contexts or no-error contexts. Versions of Mac OS X earlier than 10.7 support
	at most OpenGL version 2.1.

	Because of this, on OS X 10.7 and later, the `GLFW_CONTEXT_VERSION_MAJOR` and
	`GLFW_CONTEXT_VERSION_MINOR` hints will cause @ref glfwCreateWindow to fail if
	given version 3.0 or 3.1. The `GLFW_OPENGL_FORWARD_COMPAT` hint must be set to
	`GLFW_TRUE` and the `GLFW_OPENGL_PROFILE` hint must be set to
	`GLFW_OPENGL_CORE_PROFILE` when creating OpenGL 3.2 and later contexts. The
	`GLFW_OPENGL_DEBUG_CONTEXT` and `GLFW_CONTEXT_NO_ERROR` hints are ignored.

	Also, on Mac OS X 10.6 and below, the `GLFW_CONTEXT_VERSION_MAJOR` and
	`GLFW_CONTEXT_VERSION_MINOR` hints will fail if given a version above 2.1,
	setting the `GLFW_OPENGL_PROFILE` or `GLFW_OPENGL_FORWARD_COMPAT` hints to
	a non-default value will cause @ref glfwCreateWindow to fail and the
	`GLFW_OPENGL_DEBUG_CONTEXT` hint is ignored.


	@section compat_vulkan Vulkan loader and API

	By default, GLFW uses the standard system-wide Vulkan loader to access the
	Vulkan API on all platforms except macOS. This is installed by both graphics
	drivers and Vulkan SDKs. If either the loader or at least one minimally
	functional ICD is missing, @ref glfwVulkanSupported will return `GLFW_FALSE` and
	all other Vulkan-related functions will fail with an @ref GLFW_API_UNAVAILABLE
	error.


	@section compat_wsi Vulkan WSI extensions

	The Vulkan WSI extensions are used to create Vulkan surfaces for GLFW windows on
	all supported platforms.

	GLFW uses the `VK_KHR_surface` and `VK_KHR_win32_surface` extensions to create
	surfaces on Microsoft Windows. If any of these extensions are not available,
	@ref glfwGetRequiredInstanceExtensions will return an empty list and window
	surface creation will fail.

	GLFW uses the `VK_KHR_surface` and `VK_MVK_macos_surface` extensions to create
	surfaces on macOS. If any of these extensions are not available, @ref
	glfwGetRequiredInstanceExtensions will return an empty list and window surface
	creation will fail.

	GLFW uses the `VK_KHR_surface` and either the `VK_KHR_xlib_surface` or
	`VK_KHR_xcb_surface` extensions to create surfaces on X11. If `VK_KHR_surface`
	or both `VK_KHR_xlib_surface` and `VK_KHR_xcb_surface` are not available, @ref
	glfwGetRequiredInstanceExtensions will return an empty list and window surface
	creation will fail.

	GLFW uses the `VK_KHR_surface` and `VK_KHR_wayland_surface` extensions to create
	surfaces on Wayland. If any of these extensions are not available, @ref
	glfwGetRequiredInstanceExtensions will return an empty list and window surface
	creation will fail.

	*/