linux下编译多线程程序， undefined reference to `pthread_create'，undefined reference to `pthread_join'

问题描述：hero@ubuntu:~/WORK/for_xc7z035/app/sdr_7010$ gcc -o ./test ./test.c
/tmp/cc7BcXdf.o: In function `main':
test.c:(.text+0x1d7): undefined reference to `pthread_create'
test.c:(.text+0x1fb): undefined reference to `pthread_create'
test.c:(.text+0x21f): undefined reference to `pthread_create'
test.c:(.text+0x233): undefined reference to `pthread_join'
test.c:(.text+0x247): undefined reference to `pthread_join'
test.c:(.text+0x267): undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status

问题原因：

  1， pthread 库不是 Linux 系统默认的库，在编译多线程程序时，需要在编译命令中添加链接libpthread.a库。

 2，忘了加上头文件#include<pthread.h>

问题解决：
    在编译中要加 -lpthread参数
    gcc  ./test.c -o ./test -lpthread