me_ipc.c

这是在linux环境下C++做的生产者和消费者问题

/*******************************ipc.c*******************************************/
#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 operationP(int sem_id){
    struct sembuf buf;
    buf.sem_op=-1;
    buf.sem_num=0;
    buf.sem_flg=600;
    if((semop(sem_id,&buf,1))<0){
        perror("operationP error");exit(EXIT_FAILURE);
    }
    return EXIT_SUCCESS;
}
int operationV(int sem_id){
    struct sembuf buf;
    buf.sem_op=1;
    buf.sem_num=0;
    buf.sem_flg=600;
    if((semop(sem_id,&buf,1))<0){
        perror("operationV 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){
        /* to create a new semaphore */
        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("semaphore 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){
        /* to create a new shared memary */
        if((shm_id=shmget(shm_key,shm_num,shm_flg))<0){
            perror("shared memary create error");exit(EXIT_FAILURE);
        }
        if((shm_buf=(char*)shmat(shm_id,0,0))<(char*)0){
            perror("sharedmemary get 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("sharedmemary get error");exit(EXIT_FAILURE);
    }
    return shm_buf;
}
/*****************ipc.c end*******************/