ipc.c

这是在linux环境下C++做的生产者和消费者问题

#include "ipc.h"
int get_ipc_id(char *proc_file,key_t key)
{FILE *pf;
int i,j;
char line[BUFSZ],colum[BUFSZ];
if((pf=fopen(proc_file,"r"))==NULL){
perror("Proc file not open");
exit(EXIT_FAILURE);
}
fgets(line,BUFSZ,pf);
while(!feof(pf)){
i=j=0;
fgets(line,BUFSZ,pf);
while(line[i]==' ')i++;
while(line[i]!=' ') colum[j++]=line[i++];
colum[j]='\0';
if(atoi(colum)!=key) continue;
j=0;
while(line[i]==' ')i++;
while(line[i]!=' ') colum[j++]=line[i++];
colum[j]='\0';
i=atoi(colum);
fclose(pf);
return i;
}
fclose(pf);
return -1;
}


int down(int sem_id){
struct sembuf buf;
buf.sem_op=-1;
buf.sem_num=0;
buf.sem_flg=SEM_UNDO;
if((semop(sem_id,&buf,1))<0){
perror("down error");
exit(EXIT_FAILURE);
}
return EXIT_SUCCESS;
}


int up(int sem_id){
struct sembuf buf;
buf.sem_op=1;
buf.sem_num=0;
buf.sem_flg=SEM_UNDO;
if((semop(sem_id,&buf,1))<0){
perror("up error");
exit(EXIT_FAILURE);
}
return EXIT_SUCCESS;
}


int set_sem(key_t sem_key,int sem_val,int sem_flg){
int sem_id;
Sem_uns sem_arg;
if((sem_id=get_ipc_id("/proc/sysvipc/sem",sem_key))<0){
if((sem_id=semget(sem_key,1,sem_flg))<0){
perror("semaphore create error");
exit(EXIT_FAILURE);
}
sem_arg.val=sem_val;
if(semctl(sem_id,0,SETVAL,sem_arg)<0){
perror("semaphor set error");
exit(EXIT_FAILURE);
}
}
return sem_id;
}

char* set_shm(key_t shm_key,int shm_num,int shm_flg){
int i,shm_id;
char* shm_buf;
if((shm_id=get_ipc_id("/proc/sysvipc/shm",shm_key))<0){
if((shm_id=shmget(shm_key,shm_num,shm_flg))<0){
perror("shareMemory set error");
exit(EXIT_FAILURE);
}
if((shm_buf=(char*)shmat(shm_id,0,0))<(char*)0){
perror("get shareMemory  error");
exit(EXIT_FAILURE);
}
for(i=0;i<shm_num;i++) shm_buf[i]=0;
}
if((shm_buf=(char*)shmat(shm_id,0,0))<(char*)0){
perror("get shareMemory  error");
exit(EXIT_FAILURE);
}
return shm_buf;
}

int set_msq(key_t msq_key,int msq_flg){
int msq_id;
if((msq_id=get_ipc_id("/proc/sysvipc/msg",msq_key))<0)
{
if((msq_id=msgget(msq_key,msq_flg))<0){
perror("MessageQueue set  error");
exit(EXIT_FAILURE);
}

}
return msq_id;
}