如何模拟生产者消费者程序？

#include "unistd.h"

#include "sys/types.h"

#include "sys/wait.h"

#include "sys/shm.h"

#include "sys/ipc.h"

#include "sys/sem.h"

#include "stdio.h"

#include "stdlib.h"

#define PERM IPC_CREAT|0777

int main()

{

int semfull;

int semempty;

int semmutexp;

int semmutexc;

int shmid;

struct sembuf semwait;

struct sembuf semsignal;

semwait.sem_num=0;

semwait.sem_op=-1;

semwait.sem_flg=0;

semsignal.sem_num=0;

semsignal.sem_op=1;

semsignal.sem_flg=0;

if((shmid=shmget(IPC_PRIVATE,sizeof(int)*13,PERM))==-1)

{

printf("Create Share Memory Error.");

exit(1);

}

semfull=semget(IPC_PRIVATE,1,PERM);

int j;

for(j=0;j<10;j++)

{

semop(semfull,&semsignal,1);

}

semempty=semget(IPC_PRIVATE,1,PERM);

semmutexp=semget(IPC_PRIVATE,1,PERM);

semop(semmutexp,&semsignal,1);

semmutexc=semget(IPC_PRIVATE,1,PERM);

semop(semmutexc,&semsignal,1);

int child1,child2,child3,child4;

int *shm_addrp1,

*shm_addrp2,

*shm_addrc1,

*shm_addrc2,

*shm_main;

shm_main=(int *)shmat(shmid,0,0);

shm_main[12]=0;

if((child1=fork())==0)

{

shm_addrp1=(int*)shmat(shmid,0,0);

shm_addrp1[10]=0;

int i;

for(i=1;i<=1000;i++)

{

semop(semfull,&semwait,1);

semop(semmutexp,&semwait,1);

printf("%d : Produce %d into shm_addr[%d]./n",getpid(),i,shm_addrp1[10]);

shm_addrp1[shm_addrp1[10]]=i;

shm_addrp1[10]=(shm_addrp1[10]+1)%10;

semop(semempty,&semsignal,1);

semop(semmutexp,&semsignal,1);

}

shmdt(shm_addrp1);

exit(0);

}

else

{

if((child2=fork())==0)

{

shm_addrc1=(int*)shmat(shmid,0,0);

shm_addrc1[11]=0;

int i;

for(i=1;i<=1000;i++)

{

semop(semempty,&semwait,1);

semop(semmutexc,&semwait,1);

shm_addrc1[12] += shm_addrc1[shm_addrc1[11]];

printf("%d : Consumer %d from shm_addr[%d],sum=%d/n",getpid(),shm_addrc1[shm_addrc1[11]],shm_addrc1[11],shm_addrc1[12]);

shm_addrc1[11]=(shm_addrc1[11]+1)%10;

semop(semfull,&semsignal,1);

semop(semmutexc,&semsignal,1);

}

shmdt(shm_addrc1);

exit(0);

}

else

{

if((child3=fork())==0)

{

shm_addrc2=(int*)shmat(shmid,0,0);

shm_addrc2[11]=0;

int i;

for(i=1;i<=1000;i++)

{

semop(semempty,&semwait,1);

semop(semmutexc,&semwait,1);

shm_addrc2[12]+=shm_addrc2[shm_addrc2[11]];

printf("%d : Consumer %d from shm_addr[%d],sum=%d/n",getpid(),shm_addrc2[shm_addrc2[11]],shm_addrc2[11],shm_addrc2[12]);

shm_addrc2[11]=(shm_addrc2[11]+1)%10;

semop(semfull,&semsignal,1);

semop(semmutexc,&semsignal,1);

}

shmdt(shm_addrc2);

exit(0);

}

else

{

if((child4=fork())==0)

{

shm_addrp2=(int*)shmat(shmid,0,0);

shm_addrp2[10]=0;

int i;

for( i=1;i<=1000;i++)

{

semop(semfull,&semwait,1);

semop(semmutexp,&semwait,1);

printf("%d : Produce %d into shm_addr[%d]./n",getpid(),i,shm_addrp2[10]);

shm_addrp2[shm_addrp2[10]]=i;

shm_addrp2[10]=(shm_addrp2[10]+1)%10;

semop(semempty,&semsignal,1);

semop(semmutexp,&semsignal,1);

}

shmdt(shm_addrp2);

exit(0);

}

else

{

waitpid(child1,NULL,0);

waitpid(child2,NULL,0);

waitpid(child3,NULL,0);

waitpid(child4,NULL,0);

semctl(semfull,2,IPC_RMID,0);

semctl(semempty,2,IPC_RMID,0);

semctl(semmutexp,2,IPC_RMID,0);

semctl(semmutexc,2,IPC_RMID,0);

shmdt(shm_main);

shmctl(shmid,IPC_RMID,0);

return 0;

}

}

}

}

}

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