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SEM_INIT(3) Library Functions Manual SEM_INIT(3) NAME sem_init - initialize an unnamed semaphore LIBRARY POSIX Real-time Library (librt, -lrt) SYNOPSIS #include <semaphore.h> int sem_init(sem_t *sem, int pshared, unsigned int value); DESCRIPTION The sem_init() function initializes the unnamed semaphore pointed to by sem to have the value value. A non-zero value for pshared specifies a shared semaphore that can be used by multiple processes. Following a successful call to sem_init(), sem can be used as an argument in subsequent calls to sem_wait(), sem_timedwait(), sem_trywait(), sem_post(), and sem_destroy(). sem is no longer valid after a successful call to sem_destroy. RETURN VALUES The sem_init() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS sem_init() will fail if: [EINVAL] value exceeds SEM_VALUE_MAX. [ENOSPC] There was memory allocation error, or the limit on available semaphores (SEM_NSEMS_MAX) has been exceeded. [EPERM] Unable to initialize a shared semaphore. SEE ALSO sem_destroy(3), sem_post(3), sem_timedwait(3), sem_trywait(3), sem_wait(3) STANDARDS sem_init() conforms to ISO/IEC 9945-1:1996 ("POSIX.1"). NetBSD 9.99 February 21, 2019 NetBSD 9.99