Headers                                              sem.h(3HEAD)



NAME
     sem.h, sem -  semaphore facility

SYNOPSIS
     #include 


DESCRIPTION
     The  header defines the following  constants  and
     structures.


     Semaphore operation flags:

     SEMUNDO    Set up adjust on exit entry.



     Command definitions for the semctl() function  are  provided
     as listed below. See semctl(2).

     GETNCNT    Get semncnt.


     GETPID     Get sempid.


     GETVAL     Get semval.


     GETAL     Get all cases of semval.


     GETZCNT    Get semzcnt.


     SETVAL     Set semval.


     SETAL     Set all cases of semval.



     The semidds structure contains the following members:

       struct ipcperm semperm     /* operation permission structure */
       unsigned short  semnsems    /* number of semaphores in set */
       timet          semotime    /* last semop() time */
       timet          semctime    /* last time changed by semctl() */






SunOS 5.11          Last change: 10 Sep 2004                    1






Headers                                              sem.h(3HEAD)



     The pidt, timet, keyt, and sizet types  are  defined  as
     described in . See types.h(3HEAD).


     A semaphore is represented by an  anonymous  structure  con-
     taining the following members:

       unsigned short semval     /* semaphore value */
       pidt          sempid     /* process ID of last operation */
       unsigned short semncnt    /* number of processes waiting for semval
                                    to become greater than current value */
       unsigned short semzcnt    /* number of processes waiting for semval
                                    to become 0 */



     The sembuf structure contains the following members:

       unsigned short semnum     /* semaphore number */
       short          semop      /* semaphore operation */
       short          semflg     /* operation flags */



     All of the symbols from  are  defined  when  this
     header is included. See ipc.h(3HEAD).

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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    


SEE ALSO
     semctl(2),      semget(2),      semop(2),      ipc.h(3HEAD),
     types.h(3HEAD), attributes(5), standards(5)












SunOS 5.11          Last change: 10 Sep 2004                    2