pipe.c

#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<io.h>

int main(void)
{
  int fd0, fd1, fd2;
  int fds[2];
  int r;
  FILE *fp;
  int i;

  fp = fopen("out.txt", "w");

  close(0);
  close(1);
  close(2);
  fd0 = open("NUL", O_RDONLY);
  fd1 = open("NUL", O_WRONLY);
  fd2 = open("NUL", O_WRONLY);
  fprintf(fp, "fd0 = %d, fd1 = %d, fd2 = %d\n", fd0, fd1, fd2);

  //create pipe 3 times
  for(i = 0;i < 3;i++) {
    r = _pipe(fds, 512, 0);
    if (r != 0) {
      fprintf(fp, "error pipe returns %d\n", r);
    } else {
      fprintf(fp, "pipe(%d,%d)\n", fds[0], fds[1]);
    }
  }

  fclose(fp);
  return 0;
}