tom.c

用五个实例来解释linux下的c编程

/* tom.c v1.0 */

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>

#define FILE "message.txt"
#define PROMPT "Please input a message: "
#define SIZ (sizeof(PROMPT)-1)

int main()
{
  int fd;
  char buf[BUFSIZ];
  ssize_t s;

  /* Prompt user to input message. */
  s = write(STDOUT_FILENO, PROMPT, SIZ);
  if (s < SIZ) {
    perror("write");
    exit(EXIT_FAILURE);
  }

  /* Read message. */
  s = read(STDIN_FILENO, &buf, BUFSIZ);

  /* Open file for write. */
  fd = open(FILE, O_CREAT | O_TRUNC | O_WRONLY, 0666);
  if(fd < 0) {
    perror("open");
  }
  /* Write message. */
  s = write(fd, &buf, s);
  /* Close file. */
  close(fd);

  exit(EXIT_SUCCESS);
}