write-one.c

這是一個AT91開發版程式碼 對MCU有興趣可以研究

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

int main(int argc, char *argv[])
{
  int p;
  char buff;
  int r;

  if (argc != 3)
  {
    fprintf(stderr, "%s file int_base_10\n", argv[0]);
    exit(EXIT_FAILURE);
  }

  p = open(argv[1], O_RDWR);
  buff = strtol(argv[2], NULL, 10);

  if (!p)
  {
    perror("fopen");
    exit(EXIT_FAILURE);
  }

  r = write(p, &buff, 1);

  if (r != 1)
  {
    perror("write");
    exit(EXIT_FAILURE);
  }

  close(p);

  return EXIT_SUCCESS;
}