[ubuntu]编译共享内存读取出现read.c:(.text+0x1a): undefined reference to `shm_open‘问题解决方案

问题log

/tmp/ccByifPx.o: In function `main':
read.c:(.text+0x1a): undefined reference to `shm_open'
read.c:(.text+0xd9): undefined reference to `shm_unlink'
collect2: error: ld returned 1 exit status

程序代码

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>#define SHM_NAME "./mac_shm"
#define SHM_SIZE 18  // MAC地址长度为17个字符，加上一个终止符int main() {// 打开共享内存对象int shm_fd = shm_open(SHM_NAME, O_RDONLY, 0666);if (shm_fd == -1) {perror("shm_open");exit(EXIT_FAILURE);}// 映射共享内存char *shm_ptr = mmap(0, SHM_SIZE, PROT_READ, MAP_SHARED, shm_fd, 0);if (shm_ptr == MAP_FAILED) {perror("mmap");exit(EXIT_FAILURE);}// 读取MAC地址printf("MAC Address: %s\n", shm_ptr);// 解除映射if (munmap(shm_ptr, SHM_SIZE) == -1) {perror("munmap");exit(EXIT_FAILURE);}// 关闭共享内存对象close(shm_fd);// 删除共享内存对象shm_unlink(SHM_NAME);return 0;
}

问题分析

编译结果实际上是说，没include相应的头文件，或是头文件不存在，man shm_open看到如下内容

解决方案

gcc shm_test.c -lrt -o shm_test