未定义的引用在Linux pthread_create的 [英] undefined reference to pthread_create in Linux
问题描述
我从<一拿起下面的演示从网上href=\"https://computing.llnl.gov/tutorials/pthreads/\">https://computing.llnl.gov/tutorials/pthreads/
#include <pthread.h>
#include <stdio.h>
#define NUM_THREADS 5
void *PrintHello(void *threadid)
{
long tid;
tid = (long)threadid;
printf("Hello World! It's me, thread #%ld!\n", tid);
pthread_exit(NULL);
}
int main (int argc, char *argv[])
{
pthread_t threads[NUM_THREADS];
int rc;
long t;
for(t=0; t<NUM_THREADS; t++){
printf("In main: creating thread %ld\n", t);
rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
if (rc){
printf("ERROR; return code from pthread_create() is %d\n", rc);
exit(-1);
}
}
pthread_exit(NULL);
}
但是,当我编译我的机器上(运行Ubuntu Linux操作系统9.04)我收到以下错误:
But when I compile it on my machine (running Ubuntu Linux 9.04) I get the following error:
corey@ubuntu:~/demo$ gcc -o term term.c
term.c: In function ‘main’:
term.c:23: warning: incompatible implicit declaration of built-in function ‘exit’
/tmp/cc8BMzwx.o: In function `main':
term.c:(.text+0x82): undefined reference to `pthread_create'
collect2: ld returned 1 exit status
这没有任何意义,我,因为头包括 pthreads.h中
,它应该有一个在pthread_create
功能。任何想法是怎么回事?
This doesn't make any sense to me, because the header includes pthread.h
, which should have the pthread_create
function. Any ideas what's going wrong?
推荐答案
这两种回答这个问题至今都的不正确的。结果
对于Linux正确的命令是:
Both answers to this question so far are incorrect.
For Linux the correct command is:
gcc -pthread -o term term.c
在一般情况下,图书馆应遵循命令行的来源和对象, -lpthread
不是选项,这是一个库规范。在仅的libpthreads.a
安装
In general, libraries should follow sources and objects on command line, and -lpthread
is not an "option", it's a library specification. On a system with only libpthread.a
installed,
gcc -lpthread ...
将无法链接。
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