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Pthread_mutex_lock Error Numbers

- lock and unlock a mutex SYNOPSIS [THR] [Option Start] #include <pthread.h>

int pthread_mutex_lock(pthread_mutex_t *
mutex);
int pthread_mutex_trylock(pthread_mutex_t *
mutex);
int pthread_mutex_unlock(pthread_mutex_t *
mutex); Pthread_mutex_lock Example alt="[Option End]" border= "0"> DESCRIPTION The mutex object referenced by mutex shall be pthread_mutex_lock return value locked by calling pthread_mutex_lock(). If the mutex is already locked, the calling thread shall block until the mutex becomes man pthread_mutex_lock available. This operation shall return with the mutex object referenced by mutex in the locked state with the calling thread as its owner. [XSI] If the mutex type is PTHREAD_MUTEX_NORMAL, deadlock detection

Pthread_mutex_trylock

shall not be provided. Attempting to relock the mutex causes deadlock. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, undefined behavior results. If the mutex type is PTHREAD_MUTEX_ERRORCHECK, then error checking shall be provided. If a thread attempts to relock a mutex that it has already locked, an error shall be returned. If

Pthread_mutex_init

a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error shall be returned. If the mutex type is PTHREAD_MUTEX_RECURSIVE, then the mutex shall maintain the concept of a lock count. When a thread successfully acquires a mutex for the first time, the lock count shall be set to one. Every time a thread relocks this mutex, the lock count shall be incremented by one. Each time the thread unlocks the mutex, the lock count shall be decremented by one. When the lock count reaches zero, the mutex shall become available for other threads to acquire. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error shall be returned. If the mutex type is PTHREAD_MUTEX_DEFAULT, attempting to recursively lock the mutex results in undefined behavior. Attempting to unlock the mutex if it was not locked by the calling thread results in undefined behavior. Attempting to unlock the mutex if it is not locked results in undefined behavior. The pthread_mutex_trylock() function shall be equivalent to pthread_mutex_lock(), except that if the mutex object

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Pthread_mutex_unlock

Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each pthread_mutex_lock error 22 other. Join them; it only takes a minute: Sign up pthread_mutex_lock returns invalid argument up vote 4 down vote favorite I am working on some C code and am having a problem with locking a mutex. The code http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_lock.html does a call to a function and this function locks a mutex to ensure a file pointer doesn't get overwritten, this works fine for several instances, probably about 10-20 separate calls of the function being called, but on the next call, pthread_mutex_lock will return with a result of 22. I've then put this result into strerror(); and got back invalid argument. What does invalid argument means, thanks for any help you can provide. c debugging pthreads mutex share|improve http://stackoverflow.com/questions/12781944/pthread-mutex-lock-returns-invalid-argument this question edited Oct 8 '12 at 12:43 vy32 9,0311661128 asked Oct 8 '12 at 12:39 Boardy 9,90554168284 add a comment| 2 Answers 2 active oldest votes up vote 4 down vote accepted Sounds like you have a threading problem or a wild point somewhere else in your program. Try printing the value of the mutex pointer. Try having another thread that simply locks the mutex and then prints to a log file the time and that the lock was successful, then unlocks the mutex. I suspect the problem is not where you are looking. Also, as other have said here, your best bet is to create a very small test program that demonstrates the problem and post it here. Chances are you won't be able to get that small program to demonstrate the error. Then slowly add all of your original code into the small program until the error returns. If it returns, you now know what caused the problem. If it doesn't return, you're done. share|improve this answer answered Oct 8 '12 at 12:43 vy32 9,0311661128 add a comment| up vote 7 down vote 22 is ENVAL error code which means invlalid argument. Make sure that you have initilized you mutex, or if at some point you have unitilized it somewhere. Also man pthread_mutex_lock says: EINVAL The mutex was created with the protocol attribute having the value PTHREAD_PRIO

- operations on mutexes Synopsis #include #include pthread_mutex_t fastmutex = PTHREAD_MUTEX_INITIALIZER; pthread_mutex_t recmutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER; pthread_mutex_t errchkmutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER; pthread_mutex_t recmutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; pthread_mutex_t errchkmutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutexattr); int pthread_mutex_lock(pthread_mutex_t *mutex); int pthread_mutex_trylock(pthread_mutex_t *mutex); int pthread_mutex_timedlock(pthread_mutex_t *mutex, const struct timespec *abs_timeout); int pthread_mutex_unlock(pthread_mutex_t *mutex); int pthread_mutex_consistent(pthread_mutex_t *mutex); int pthread_mutex_destroy(pthread_mutex_t *mutex); Description A mutex is a MUTual EXclusion device, and is useful for protecting shared data structures from concurrent modifications, and implementing critical sections and monitors. A mutex has two possible states: unlocked (not owned by any thread), and locked (owned by one thread). A mutex can never be owned by two different threads simultaneously. A thread attempting to lock a mutex that is already locked by another thread is suspended until the owning thread unlocks the mutex first. pthread_mutex_init initializes the mutex object pointed to by mutex according to the mutex attributes specified in mutexattr. If mutexattr is NULL, default attributes are used instead. The type of a mutex determines whether it can be locked again by a thread that already owns it. The default type is “normal�. See pthread_mutexattr_init(3) for more information on mutex attributes. Variables of type pthread_mutex_t can also be initialized statically, using the constants PTHREAD_MUTEX_INITIALIZER (for normal “fast� mutexes), PTHREAD_RECURSIVE_MUTEX_INITIALIZER (for recursive mutexes), and PTHREAD_ERRORCHECK_MUTEX_INITIALIZER (for error checking mutexes). In the Pthreads-w32 implementation, an application should still call pthread_mutex_destroy at some point to ensure that any resources consumed by the mutex are released. Any mutex type can be initialized as a robust mutex. See pthread_mutexattr_init(3) for more information as well as the sec

 

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pthread_mutex_lock error handling

Pthread mutex lock Error Handling p pthread mutex lock pthread mutex t i mutex i int pthread mutex trylock pthread mutex t i mutex i int pthread mutex unlock pthread mutex t i mutex i DESCRIPTION The mutex object referenced by mutex is locked by calling pthread mutex lock If the mutex is already locked the calling thread blocks until the mutex Pthread mutex lock Example becomes available This operation returns with the mutex object referenced by mutex pthread mutex lock return value in the locked state with the calling thread as its owner If the mutex type is PTHREAD

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pthread_mutex_lock error codes

Pthread mutex lock Error Codes p pthread mutex lock pthread mutex t i mutex i int pthread mutex trylock pthread mutex t i mutex i int pthread mutex unlock pthread mutex t i mutex i DESCRIPTION The mutex object referenced by mutex is locked by calling pthread mutex lock If the mutex is already locked the calling thread blocks until the mutex becomes available Pthread mutex lock Example This operation returns with the mutex object referenced by mutex in the pthread mutex lock return value locked state with the calling thread as its owner If the mutex type is PTHREAD

pthread_mutex_lock error code 22

Pthread mutex lock Error Code p here for a quick overview of the site Help Center Detailed answers to any pthread mutex lock mutex failed with error questions you might have Meta Discuss the workings and policies of Mutex Lock Failed this site About Us Learn more about Stack Overflow the company Business Learn more about hiring Pthread Mutex Example developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is Pthread mutex initializer a community of million programmers just like you helping each other

pthread_mutex_lock error checking

Pthread mutex lock Error Checking p pthread mutex lock pthread mutex t i mutex i int pthread mutex trylock pthread mutex t i mutex i int pthread mutex unlock pthread mutex t i mutex i DESCRIPTION The mutex object referenced by mutex is locked by calling pthread mutex lock If the mutex is already locked the calling Pthread mutex lock Example thread blocks until the mutex becomes available This operation returns with pthread mutex lock return value the mutex object referenced by mutex in the locked state with the calling thread as its Man Pthread mutex lock owner If the