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#include 
#include 
#include 

#if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)
/* 共用体 semun の定義は <sys/sem.h> に含まれている */
#else
/* X/OPEN に従うならば自分自身で以下のように定義しなければならない */
union semun {
     int val;                    /* value for SETVAL */
     struct semid_ds *buf;       /* buffer for IPC_STAT, IPC_SET */
     unsigned short int *array;  /* array for GETALL, SETALL */
     struct seminfo *__buf;      /* buffer for IPC_INFO */
};
#endif

int  semctl  (int  semid, int semnum, int cmd, union semun
arg)

/* The user should define a union like the following to use it for arguments
   for `semctl'.

   union semun
   {
     int val;                           <= value for SETVAL
     struct semid_ds *buf;              <= buffer for IPC_STAT & IPC_SET
     unsigned short int *array;         <= array for GETALL & SETALL
     struct seminfo *__buf;             <= buffer for IPC_INFO
   };

   Previous versions of this file used to define this union but this is
   incorrect.  One can test the macro _SEM_SEMUN_UNDEFINED to see whether
   one must define the union or not.  */
#define _SEM_SEMUN_UNDEFINED    1