在Linux中对pthread_create的未定义引用

#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);
}

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

gcc -pthread -o term term.c

gcc -o term term.c -lpthread

gcc -o test test.c -pthread

#5 楼

首先，如果您继续阅读以下教程，则会在下表中列出用于pthreads代码的几个编译命令示例：

https://computing.llnl.gov/tutorials/pthreads/ #Compiling

add_compile_options(-pthread)

SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")

find_package (Threads REQUIRED)

target_link_libraries(helloworld
    ${CMAKE_THREAD_LIBS_INIT}
)

SYNOPSIS
       #include <pthread.h>

       int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
                          void *(*start_routine) (void *), void *arg);


       Compile and link with -pthread.
       ....

LDFLAGS='-lpthread'