undefined reference to `pthread_create' in Linux

情况说明

在进行Linux系统多线程编程学习时，使用了

pthread_create

代码：

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
/* this data is shared by the threads */
int sum;
/* threads call this function */
void *runner(void *param);

int main(int argc, char *argv[])
{
pthread_t tid;
pthread_attr_t attr;
if (argc != 2){
fprintf(stderr, "usage: a.out <integer value>\n");
return -1;
}
if (atoi(argv[1]) < 0){
fprintf(stderr, "%d must be >= 0\n", atoi(argv[1]));
return -1;
}
/* get default attributes */
pthread_attr_init(&attr);
/* create the thread */
pthread_create(&tid, &attr, runner, argv[1]);
/* wait for the thread to exit */
pthread_join(tid, NULL);

printf("the sum is %d\n", sum);
return 0;
}

void *runner(void *param){
int i, upper = atoi(param);
sum = 0;
for(i = 0; i <= upper; i++){
sum += i;
}
pthread_exit(0);
}

报错：

/usr/bin/ld: /tmp/ccAmXOUU.o: in function `main':
4-9-pthreads.c:(.text+0xcd): undefined reference to `pthread_create'
/usr/bin/ld: 4-9-pthreads.c:(.text+0xde): undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status

解决办法

在编译时，加上所需要的库，即

pthread

gcc -o test test.c -pthread

参考文章

https://stackoverflow.com/questions/1662909/undefined-reference-to-pthread-create-in-linux