linux共享內存的使用--測試程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>

#define MB (1 << 20)
#define SHM_MODE 0600

int main(int argc, char **argv)
{
    int shmid = 0;
    char *shmptr = NULL;

    unsigned long long shmsize = strtoul(argv[1], NULL, 10);
    printf("shmsize = %lu\n", shmsize * MB);
    unsigned long long flag = strtoul(argv[2], NULL, 16);
    printf("flag = %lu\n", flag);

    shmid = shmget(IPC_PRIVATE, shmsize * MB, flag);
    if(shmid<0)
    {
        fprintf(stderr, "shmget: %s\n", strerror(errno));
        exit(1);
    }

    shmptr = shmat( shmid, 0, 0);
    if(shmptr==(void *)-1)
    {
        fprintf(stderr, "shmat: %s\n", strerror(errno));
        exit(1);
    }

    printf("shm(%u) from 0x%x to 0x%x.\n", shmsize, shmptr, shmptr+shmsize);

    memset(shmptr, 0x41, shmsize); 

    getchar();

    memset(shmptr, 0, shmsize); 

    if( shmctl(shmid, IPC_RMID, 0) < 0)
    {
        fprintf(stderr, "shmctl: %s\n", strerror(errno));
        exit(1);
    }

    return 0;
}