3bf7994fe2
Case fallthrough warnings can be suppressed using the __fallthrough__
compiler attribute. Unfortunately, not all compilers have this
attribute, or even have __has_attribute to check if they have the
__fallthrough__ attribute. [[fallthrough]] is also available in C++17
and the next C2x, but not everyone uses C++17 or C2x.
So define the SDL_FALLTHROUGH macro to deal with those problems - if we
are using C++17 or C2x, it expands to [[fallthrough]]; else if the
compiler has __has_attribute and has the __fallthrough__ attribute, then
it expands to __attribute__((__fallthrough__)); else it expands to an
empty statement, with a /* fallthrough */ comment (it's a do {} while
(0) statement, because users of this macro need to use a semicolon,
because [[fallthrough]] and __attribute__((__fallthrough__)) require a
semicolon).
Clang before Clang 10 and GCC before GCC 7 have problems with using
__attribute__ as a sole statement and warn about a "declaration not
declaring anything", so fall back to using the /* fallthrough */ comment
if we are using those older compiler versions.
Applications using SDL are also free to use this macro (because it is
defined in begin_code.h).
All existing /* fallthrough */ comments have been replaced with this
macro. Some of them were unnecessary because they were the last case in
a switch; using SDL_FALLTHROUGH in those cases would result in a compile
error on compilers that support __fallthrough__, for having a
__attribute__((__fallthrough__)) statement that didn't immediately
precede a case label.
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| .github | ||
| acinclude | ||
| android-project | ||
| android-project-ant | ||
| build-scripts | ||
| cmake | ||
| debian | ||
| docs | ||
| include | ||
| src | ||
| test | ||
| VisualC | ||
| VisualC-WinRT | ||
| visualtest | ||
| wayland-protocols | ||
| Xcode | ||
| Xcode-iOS | ||
| .gitignore | ||
| Android.mk | ||
| autogen.sh | ||
| BUGS.txt | ||
| cmake_uninstall.cmake.in | ||
| CMakeLists.txt | ||
| configure | ||
| configure.ac | ||
| CREDITS.txt | ||
| INSTALL.txt | ||
| LICENSE.txt | ||
| Makefile.in | ||
| Makefile.minimal | ||
| Makefile.os2 | ||
| Makefile.pandora | ||
| Makefile.psp | ||
| Makefile.wiz | ||
| README-SDL.txt | ||
| README.md | ||
| sdl2-config-version.cmake.in | ||
| sdl2-config.cmake.in | ||
| sdl2-config.in | ||
| sdl2.m4 | ||
| sdl2.pc.in | ||
| SDL2.spec.in | ||
| SDL2Config.cmake | ||
| TODO.txt | ||
| WhatsNew.txt | ||
Simple DirectMedia Layer (SDL) Version 2.0
Simple DirectMedia Layer is a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware via OpenGL and Direct3D. It is used by video playback software, emulators, and popular games including Valve's award winning catalog and many Humble Bundle games.
More extensive documentation is available in the docs directory, starting with README.md
Enjoy!
Sam Lantinga (slouken@libsdl.org)