pthread mutex init return value

If attr is NULL the default attributes are used, otherwise attr should be initialized by calling pthread_mutexattr_init(3) . System resources (other than memory) are unavailable. pthread_mutex_init initializes the mutex object pointed to by mutex according to the mutex attributes specified in mutexattr. Once a condition variable is created, it cannot be validly copied or moved to a new location. The class would need to expose lock/unlock methods which operator on the instance-variable in-place. If mutexattr is NULL , default attributes are used instead. ERRORS pthread_mutex_init() will fail if: [EAGAIN] The system temporarily lacks the resources to create another mutex. The pthread_mutex_init() function creates a new mutex, with attributes specified with attr. • barrier_wait • Block until a specified number of threads reach the barrier. Some pthread library functions pthread_create pthread_join pthread_mutex_lock pthread_mutex_unlock pthread_barrier_wait. Results are undefined if pthread_mutexattr_init () is called specifying an already initialized attr attributes object. Note If there exists a thread holding this mutex, this function returns 0 with mutex not being destroyed. On error, one of the following values is returned: EAGAIN . attr Pointer to the attributes object that defines the characteristics of the mutex to be initialized. pthread_mutex_t __aio_requests_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; /* When you add a request to the list and there are idle threads present, you signal this condition variable. If attr is NULL the default attributes are used. Note attr is ignored. On success, pthread_mutex_init() returns 0. [EINVAL] The value specified by attr is invalid. pthread_barrier_init() is implemented with FreeRTOS event group. SEE ALSO. May be one of PTHREAD_PRIO_NONE, or PTHREAD_PRIO_INHERIT, PTHREAD_PRIO_PROTECT. Insufficient memory exists to create the mutex attribute object. pthread_mutex_unlock unlocks the given mutex. All Data Structures Namespaces Files Functions Variables Typedefs Defines. pthread_mutex_init() The type of a mutex determines whether it can be locked again by a thread that already owns it. My Windows version is 10.0.17134.167. Implement a general counting semaphore using Pthread mutex and condition variable. value On success, pthread_mutexattr_init() returns 0. CONFORMANCE. pthread_mutex_timedlock() may fail if: [EINVAL] The mutex was created with the protocol attribute having the value PTHREAD_PRIO_PROTECT and the calling thread's priority is higher than the mutex current priority ceiling; or the process or thread would have blocked, and the timeout parameter specified a nanoseconds field value less than zero or greater than or equal to 1000 million. ENOMEM . The value of prioceiling must be between the values returned by sched _ get _ priority _ min () and sched _ get _ priority _ max (), inclusive. If the parameter attr is NULL, the default mutex attributes are used. Note that pthread_mutex_t, pthread_rwlock_t, and os_unfair_lock are value types, not reference types. pthread_mutexattr_init initializes the mutex attribute object attr and fills it with default values for the attributes. EOK : Mutex was initialized successfully. EDEADLK A deadlock condition would occure if the thread blocked waiting for the mutex. pthread_mutexattr_init initializes the mutex attribute object attr and fills it with default values for the attributes. EINVAL The value specified by mutex is not a valid mutex. Insufficient memory exists to initialize the mutex. EFAULT . • lock/acquire • Block until the mutex is available, then claim it. pthread_mutexattr_destroy destroys a mutex attribute object, which must not be reused until it is reinitialized. LIBRARY DECthreads POSIX 1003.1c Library ... your program must use a mutex to protect the integrity of the attributes object's contents. Sorry again that I can't provide a backtrace but I hope this is information somewhat useful to you. Return the value of the mutex protocol attribute.. The pthread_mutexattr_destroy() function destroys a mutex attribute object (making it uninitialized). [EINVAL] The value specified by attr is invalid. On error, one of the following values is returned: ENOMEM . Authorities and Locks. Return values: EINVAL : attrs is not initialized. RETURN VALUE top The outpt is pthread_mutex_init errno=95 I googled for a whole day but get nothing. To ensure count fits in event group, count may be at most 8 when configUSE_16_BIT_TICKS is 1; it may be at most 24 otherwise. … [ENOMEM] The process cannot allocate enough memory to create another mutex. RETURN VALUES If successful, pthread_mutex_init() will return zero and put the new mutex configUSE_16_BIT_TICKS is configured in application FreeRTOSConfig.h file, which defines how many bits tick count type has. • unlock/release • Release a mutex. To work, the pthread_mutex_t would need to be initialized in-place within a class instance, and never copied out. Attempting to initialise an already initialised condition variable attributes object results in undefined behaviour. • Gives access to the thread function’s return value. [ENOMEM] The process cannot allocate enough memory to create another mutex. The pthread_mutex_init() function creates a new mutex, with attributes specified with attr. RETURN VALUES. The default pshared attribute for mutex attributes objects is PTHREAD_PROCESS_PRIVATE. int pthread_mutex_init (pthread_mutex_t * mutex, ... Initializes the mutex. pthread_mutex_init(), pthread_mutex_destroy() - initialize or destroy a mutex SYNOPSIS PARAMETERS mutex Pointer to the mutex to be initialized or destroyed. EBUSY The mutex specified by mutex is already locked. attr is an invalid pointer. None. Input Parameters: attr. The function pthread_condattr_init initialises a condition variable attributes object attr with the default value for all of the attributes defined by the implementation. Value Types. The pthread_mutex_setprioceiling() function acquires the named mutex, then changes the mutex's priority ceiling and releases the mutex. My WSL version is Linux version 4.4.0-17134-Microsoft (Microsoft@Microsoft.com) (gcc version 5.4.0 (GCC) ) #137-Microsoft Thu Jun 14 18:46:00 PST 2018. AUTHOR¶ Xavier Leroy SEE ALSO¶ pthread_condattr_init(3), pthread_mutex_lock(3), pthread_mutex_unlock(3), gettimeofday(2), nanosleep(2). The results of destroying an uninitialized mutex attributes object are undefined. A pointer to the mutex attributes to be queried. If the pointer is NULL, default attributes are used. EINVAL . A mutex can be initialized in two ways: by a call to pthread_mutex_init(); or by assignment of PTHREAD_MUTEX_INITIALIZER. ERRORS. EXAMPLE¶ Consider two shared variables x and y, protected by the mutex mut, and a condition variable cond that is to be signaled whenever x becomes greater than y. EINVAL . Parameter prototype: int pthread_cond_init(pthread_cond_t *cv,const pthread_condattr_t *cattr); cv: condition cattr: usually NULL E.g: pthread_cond_t cond; pthread_cond_init(&cond,NULL); Return value: return 0 if successful, any other value indicates failure. ... RETURN VALUE pthread_mutexattr_init, pthread_mutexattr_destroy and pthread_mutexattr_gettype always return 0. attr does not point to writable memory. The user provided location in which to store the protocol value. Thank you for your help. Returned Value: If successful, the pthread_mutexattr_getprotocol() function will return zero (OK). The return value of pthread_mutex_trylock() in Mutex.h is EDEADLK with the new threading library (it was EBUSY with the old one) which causes the ThreadSyscallException to be thrown. mutex or attr is an invalid pointer. In all cases the pthread_mutex_trylock() routine will not block the current running thread. If it is of the ``recursive'' kind, it decrements the locking count of the mutex (number of pthread_mutex_lock operations performed on … Generated on 2019-Mar-30 from project glibc revision glibc-2.29.9000-166-g656dd306d4 Powered by Code Browser 2.1 Generator usage only permitted with license. Once a mutex attributes object has been destroyed, it can be reinitialized with pthread_mutexattr_init(). pthread_cond_t cond1 = PTHREAD_MUTEX_INITIALIZER; pthread_cond_init(&cond2, NULL); pthread_cond_init(&cond3, &attr); All four condition variables are created with the default condition attributes. pthread_cond_destroy (destroy): Required header files: #include RETURN VALUES. Code Browser 2.1 Generator usage only permitted with license. ERRORS pthread_mutex_init() will fail if: [EAGAIN] The system temporarily lacks the resources to create another mutex. protocol. pthread_attr_init - Initializes a thread attributes object. Passing NULL is equivalent to passing a mutex attribute object with all attributes set to their default values. Every condition variable must eventually be destroyed with pthread_cond_destroy(). pthread_mutex_init The pthread_mutex_init() function initializes the mutex referenced by mutex with the attributes attr. attr does not refer to a valid condition variable attribute object. The function pthread_mutexattr_init initialises a mutex attributes object attr with the default value for all of the attributes defined by the implementation. EFAULT . The pthread_mutexattr_init() function shall initialize a mutex attributes object attr with the default value for all of the attributes defined by the implementation. The effect of initialising an already initialised mutex attributes object is undefined. The mutex is assumed to be locked and owned by the calling thread on entrance to pthread_mutex_unlock.If the mutex is of the ``fast'' kind, pthread_mutex_unlock always returns it to the unlocked state. 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