Almost nothing checks these return values, and there's no reason a valid
lock should fail to operate. The cases where a lock isn't valid (it's a
bogus pointer, it was previously destroyed, a thread is unlocking a lock it
doesn't own, etc) are undefined behavior and always were, and should be
treated as an application bug.
Reference Issue #8096.
It needs to be SDL_RELEASE_GENERIC, because it releases both exclusive
(writer) and shared (reader) locks.
Without this fix, clang's `-Wthread-safety` tests generate incorrect warnings.
Reference Issue #8096.
The annotations have been added to SDL_mutex.h and have been made public so applications can enable this for their own code.
Clang assumes that locking and unlocking can't fail, but SDL has the concept of a NULL mutex, so the mutex functions have been changed not to report errors if a mutex hasn't been initialized. We do have mutexes that might be accessed when they are NULL, notably in the event system, so this is an important change.
This commit cleans up a bunch of rare race conditions in the joystick and game controller code so now everything should be completely protected by the joystick lock.
To test this, change the compiler to "clang -Wthread-safety -Werror=thread-safety -DSDL_THREAD_SAFETY_ANALYSIS"
I ran this script in the include directory:
```sh
sed -i '' -e 's,#include "\(SDL.*\)",#include <SDL3/\1>,' *.h
```
I ran this script in the src directory:
```sh
for i in ../include/SDL3/SDL*.h
do hdr=$(basename $i)
if [ x"$(echo $hdr | egrep 'SDL_main|SDL_name|SDL_test|SDL_syswm|SDL_opengl|SDL_egl|SDL_vulkan')" != x ]; then
find . -type f -exec sed -i '' -e 's,#include "\('$hdr'\)",#include <SDL3/\1>,' {} \;
else
find . -type f -exec sed -i '' -e '/#include "'$hdr'"/d' {} \;
fi
done
```
Fixes https://github.com/libsdl-org/SDL/issues/6575
Ryan C. Gordon
Sam Lantinga
SDL Wiki Bot
Anonymous Maarten
Sylvain
Pierre Wendling