mem_write.c

来自「LINUX内核编程的一些程序例子」· C语言 代码 · 共 54 行

/** @file mem_write.c
 *
 * @author marco corvi <[e-mail]>
 * @date   mar 2003
 *
 * \brief write test for the mem_tty driver
 *
 */ 

#include <stdio.h>      // printf
#include <stdlib.h>     // exit
#include <sys/types.h>  // open
#include <sys/stat.h>   // open
#include <fcntl.h>      // open
#include <unistd.h>     // read close sleep
#include <errno.h>      // errno

int 
main( int argc, char ** argv )
{
  int fd;
  char ch;
  int i;
  char * str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
  int len;

  len = 0;
  while ( str[len] ) len++;

  fprintf(stderr, "mem_write: string %s len %d\n", str, len);

  fd = open( argv[1], O_WRONLY | O_NDELAY );
  if ( fd < 0 ) {
    fprintf(stderr, "Error: unable to open %s (errno %d)\n", argv[1], errno);
    exit( 1 );
  }

  for (i=0; i<10; i++) {
    if ( write( fd, str, len ) <= 0) {
      perror( "write str error");
      break;
    }
    ch = '\n';
    if ( write( fd, &ch, 1 ) <= 0) {
      perror( "write \'\\n\' error");
      break;
    }
    printf("Written string nr. %d\n", i);
    sleep( 1 );
  }
  close( fd );
  exit( 0 );
}