Linux下undefined reference to ‘pthread_create’问题解决

root@ubuntu:/test/linux/20160218# gcc threadid.c
/tmp/cc2buUlJ.o: In function `main':
threadid.c:(.text+0x2e6): undefined reference to `pthread_create'
collect2: ld returned 1 exit status
root@ubuntu:/test/linux/20160218# gcc -lpthread threadid.c
root@ubuntu:/test/linux/20160218# ./a.out
main thread: pid 5720 tid 3077879488 (0xb774b6c0)
new thread:  pid 5720 tid 3077876592 (0xb774ab70)
root@ubuntu:/test/linux/20160218#