Question

我有两个文件。 sim.c 和 devices.c 。

这里是 sim.c

...
#include "devices.h"

int main(int argc, char **argv) {
  pthread_t *tid;

  tid = (pthread_t *) malloc(sizeof(pthread_t) * 3);

  // this is where I start the 3 threads located in devices.c
  if (pthread_create(&tid[0], NULL, device_one, NULL)) {
    exit(1);
  }
  if (pthread_create(&tid[1], NULL, device_two, NULL)) {
    exit(1);
  }
  if (pthread_create(&tid[2], NULL, device_three, NULL)) {
    exit(1);
  }

  // wait for 3 threads to finish
  int i;
  for (i = 0; i < 3; i++) {
    if (pthread_join(tid[i], NULL)) {
      exit(1);
    }
  }
}

此处 devices.c

...
#include "devices.h"

extern void *device_one(void *arg) {
  printf("device one is called\n");
  return NULL;
}

extern void *device_two(void *arg) {
  printf("device two is called\n");
  return NULL;
}

extern void *device_three(void *arg) {
  printf("device three is called\n");
  return NULL;
}

这是 devices.h

#ifndef DEVICES_H
#define DEVICES_H

extern void *device_one(void *arg);
extern void *device_two(void *arg);
extern void *device_three(void *arg);

然而，当我编译时，我在sim.c下得到3个错误未定义对＆quot; device_one＆＃39;的引用未定义引用＆quot; device_two＆＃39;
未定义对＆quot; device_three＆＃39;

的引用

Answer 1

错误表明您在编译devices（包含sim.c）时未与main模块建立关联。您可以编译为：

gcc sim.c devices.c -I.

或者你可以创建一个makefile：

CC = gcc
CFLAGS = -I.
DEPS = devices.h
OBJ = sim.o devices.o
LDLIBS = -pthread

%.o: %.c $(DEPS)
        $(CC) -c -o $@ $< $(CFLAGS)

sim: $(OBJ)
        $(CC) -o $@ $^ $(CFLAGS) $(LDLIBS)

.PHONY: clean

clean:
        rm -rf $(OBJ)

无法从另一个文件中的函数创建线程

1 个答案: