some-usable-scripts/C_Language/ncurses_semaphores/sema.c

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#include <stdlib.h>
#include <assert.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdarg.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
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#include "sema.h"
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typedef unsigned short int ushort;
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int creat_sem(key_t cle,int val)
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{
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int semid;
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union semun{
int val;
struct semid_ds *buf;
ushort *array;
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} arg;
if((semid=semget(cle,1,0666+IPC_CREAT+IPC_EXCL))>= 0)
{
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arg.val=val;
if(semctl(semid,0,SETVAL,arg)< 0)
semid = -1;
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}
return(semid);
}
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int del_sem(key_t cle)
{
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return(semctl((semget(cle,0,0)),0,IPC_RMID,0));
}
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int open_sem(key_t cle)
{
return(semget(cle,0,0));
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}
void P(int semid)
{
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struct sembuf psembuf;
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psembuf.sem_op = -1;
psembuf.sem_flg = 0;
psembuf.sem_num = 0;
semop(semid,&psembuf,1);
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}
void V(int semid)
{
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struct sembuf vsembuf;
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vsembuf.sem_op = 1;
vsembuf.sem_flg = 0;
vsembuf.sem_num = 0;
semop(semid,&vsembuf,1);
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}