diff options
Diffstat (limited to 'sysdeps/mach/bits')
| -rw-r--r-- | sysdeps/mach/bits/libc-lock.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/sysdeps/mach/bits/libc-lock.h b/sysdeps/mach/bits/libc-lock.h index 79a1e00464..17eeefcdb5 100644 --- a/sysdeps/mach/bits/libc-lock.h +++ b/sysdeps/mach/bits/libc-lock.h @@ -75,6 +75,27 @@ typedef cthread_key_t __libc_key_t; (*__save_FCT)(__save_ARG); \ } +/* Use mutexes as once control variables. */ + +struct __libc_once + { + __libc_lock_t lock; + int done; + }; + +#define __libc_once_define(CLASS,NAME) \ + CLASS struct __libc_once NAME = { MUTEX_INITIALZER, 0 } + + +/* Call handler iff the first call. */ +#define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \ + do { \ + __libc_lock_lock (ONCE_CONTROL.lock); \ + if (!ONCE_CONTROL.done) \ + (INIT_FUNCTION) (); \ + ONCE_CONTROL.done = 1; \ + __libc_lock_lock (ONCE_CONTROL.lock); \ + } while (0) #ifdef _LIBC /* We need portable names for some functions. E.g., when they are |