test.c

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/stat.h>

volatile int fd;

void* thread_proc(void* arg) {
  int r;
  sleep(1);
  printf("Closing...\n");
  r = close(fd);
  printf("close %d %s\n", r, r >= 0 ? "" : strerror(errno)); 
  printf("Closed\n");
  return NULL;
}

int main(int argc, char* argv[]) {
  char buf[1024*1024];
  int r;
  pthread_t ptid;
  
  fd = open("a", O_RDONLY);
  assert(fd >= 0);
  printf("fd: %d\n", fd);
 
  pthread_create(&ptid, NULL, thread_proc, NULL); 
  
  for (;;) {
    r = read(fd, buf, sizeof buf);
    printf("read %d %s\n", r, r >= 0 ? "" : strerror(errno));
  }  

  return 0;
}

Terminal 1

$ mkfifo a
$ cat > a   #leave running, don't enter anything

Terminal 2

$ gcc test.c -lpthread -Wall
$ ./a.out