diff options
| -rw-r--r-- | mysys/my_pthread.c | 37 |
1 files changed, 31 insertions, 6 deletions
diff --git a/mysys/my_pthread.c b/mysys/my_pthread.c index 15ca8934bcb..12a49a7a916 100644 --- a/mysys/my_pthread.c +++ b/mysys/my_pthread.c @@ -434,17 +434,42 @@ int my_pthread_cond_timedwait(pthread_cond_t *cond, In HP-UX-10.20 and other old Posix 1003.4a Draft 4 implementations pthread_mutex_trylock returns 1 on success, not 0 like pthread_mutex_lock + + From the HP-UX-10.20 man page: + RETURN VALUES + If the function fails, errno may be set to one of the following + values: + Return | Error | Description + _______|__________|_________________________________________ + 1 | | Successful completion. + 0 | | The mutex is locked; therefore, it was + | | not acquired. + -1 | [EINVAL] | The value specified by mutex is invalid. + +*/ +/* We defined pthread_mutex_trylock as a macro in my_pthread.h, we have + to undef it here to prevent infinite recursion! Note that this comment + documents the pushed bugfix, not just the the code itself here. That is why + this comment is good here. */ + #undef pthread_mutex_trylock +/* +This function returns 0 if we are able successfully lock the mutex. If +the mutex cannot be locked or there is an error, then returns != 0 +*/ int my_pthread_mutex_trylock(pthread_mutex_t *mutex) { - int error=pthread_mutex_trylock(mutex); - if (error == 1) /* Safety if the lib is fixed */ - return 0; /* Mutex was locked */ - if (error == -1) /* Safety if the lib is fixed */ - error=errno; - return error; + int error = pthread_mutex_trylock(mutex); + + if (error == 1) + return 0; /* success */ + + if (error == -1) + error=errno; /* parameter invalid */ + + return 1; /* we were not able to lock the mutex */ } #endif |