ead 1.1;
access;
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root:1.1; strict;
comment @ * @;
1.1
date 2014.05.14.23.41.10; author root; state Exp;
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desc
@semaphore with semget,semctl,semop.
@
1.1
log
@Initial revision
@
text
@#include<stdio.h>
#include<linux/sem.h>
#include<stdlib.h>
int main()
{
int i,aa,aaa;
union semun u;
u.val=1;
struct sembuf sem1;
sem1.sem_num=0;
sem1.sem_op=-1;
sem1.sem_flg=SEM_UNDO;
aa=semget((key_t)1234,1,IPC_CREAT|0777);
if(aa<0)
{
perror(“semget failure\n”);
goto OUT;
}
aaa=semctl(aa,0,SETVAL,0);
if(aaa<0)
{
perror(“segctl failure\n”);
goto OUT;
}
semop(aa,&sem1,0);
for(i=1;i<=3;i++)
{
printf(“hello i m into critical section =%d\n”,getpid());
sleep(2);
printf(” i m into critical section =%d\n”,getpid());
sleep(2);
printf(“bye i m into critical section =%d\n”,getpid());
}
sem1.sem_num=0;
sem1.sem_op=1;
sem1.sem_flg=SEM_UNDO;
semop(aa,&sem1,0);
return 0;
OUT:
return -1;
}
@
