SDL_mutexP (3) - Linux Manuals
SDL_mutexP: Lock a mutex
NAME
SDL_mutexP - Lock a mutexSYNOPSIS
#include "SDL.h" #include "SDL_thread.h"
int SDL_mutexP(SDL_mutex *mutex);
DESCRIPTION
Locks the mutex, which was previously created with SDL_CreateMutex. If the mutex is already locked then SDL_mutexP will not return until it is unlocked. Returns 0 on success, or -1 on an error.
SDL also defines a macro #define SDL_LockMutex(m) SDL_mutexP(m).
SEE ALSO
SDL_CreateMutex, SDL_mutexV