Manual Pages for UNIX Operating System command usage for man sem_init

Standard C Library Functions                         sem_init(3C)



NAME
     sem_init - initialize an unnamed semaphore

SYNOPSIS
     #include 

     int sem_init(sem_t *sem, int pshared, unsigned int value);


DESCRIPTION
     The sem_init() function is used to  initialize  the  unnamed
     semaphore  referred  to by sem. The value of the initialized
     semaphore  is  value.  Following  a   successful   call   to
     sem_init(), the semaphore may be used in subsequent calls to
     sem_wait(3C),     sem_trywait(3C),     sem_post(3C),     and
     sem_destroy(3C).  This  semaphore  remains  usable until the
     semaphore is destroyed.


     If the pshared argument has a non-zero value, then the sema-
     phore is shared between processes; in this case, any process
     that can access the semaphore sem can use sem for performing
     sem_wait(3C),     sem_trywait(3C),     sem_post(3C),     and
     sem_destroy(3C) operations.


     Only sem itself may be used for performing  synchronization.
     The  result  of  referring  to  copies  of  sem  in calls to
     sem_wait(3C),     sem_trywait(3C),     sem_post(3C),     and
     sem_destroy(3C), is undefined.


     If the pshared argument  is  zero,  then  the  semaphore  is
     shared  between  threads  of the process; any thread in this
     process   can   use   sem   for   performing   sem_wait(3C),
     sem_trywait(3C),  sem_post(3C),  and  sem_destroy(3C) opera-
     tions. The use of the semaphore by threads other than  those
     created in the same process is undefined.


     Attempting to initialize an  already  initialized  semaphore
     results in undefined behavior.


     The sem_open(3C) function is used with named semaphores.

RETURN VALUES
     Upon successful completion,  the  function  initializes  the
     semaphore in sem. Otherwise, it returns -1 and sets errno to
     indicate the error.





SunOS 5.11           Last change: 9 Jul 2009                    1






Standard C Library Functions                         sem_init(3C)



ERRORS
     The sem_init() function will fail if:

     EINVAL     The value argument exceeds  SEM_VALUE_MAX.


     ENOSPC     A resource required to initialize  the  semaphore
                has been exhausted, or the resources have reached
                the limit on semaphores (SEM_NSEMS_MAX).


     ENOSYS     The sem_init() function is not supported  by  the
                system.


     EPERM      The process lacks the appropriate  privileges  to
                initialize the semaphore.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    | ATTRIBUTE TYPE              | ATTRIBUTE VALUE             |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     sem_destroy(3C), sem_open(3C),  sem_post(3C),  sem_wait(3C),
     attributes(5), standards(5)
















SunOS 5.11           Last change: 9 Jul 2009                    2