nsz Git - musl/blob - src/thread/pthread_mutexattr_setprotocol.c

   1 #include "pthread_impl.h"
   2 #include "syscall.h"
   3
   4 static volatile int check_pi_result = -1;
   5
   6 int pthread_mutexattr_setprotocol(pthread_mutexattr_t *a, int protocol)
   7 {
   8         int r;
   9         switch (protocol) {
  10         case PTHREAD_PRIO_NONE:
  11                 a->__attr &= ~8;
  12                 return 0;
  13         case PTHREAD_PRIO_INHERIT:
  14                 r = check_pi_result;
  15                 if (r < 0) {
  16                         volatile int lk = 0;
  17                         r = -__syscall(SYS_futex, &lk, FUTEX_LOCK_PI, 0, 0);
  18                         a_store(&check_pi_result, r);
  19                 }
  20                 if (r) return r;
  21                 a->__attr |= 8;
  22                 return 0;
  23         case PTHREAD_PRIO_PROTECT:
  24                 return ENOTSUP;
  25         default:
  26                 return EINVAL;
  27         }
  28 }