dev_test.c

操作系统课程设计 有进程同步问题 内存管理 设备管理

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

main()
{
int testdev;
int i ;
char buf[50]="pear to dev! ";
printf("the program  tt is  running!!\n");
testdev = open("/dev/test",O_RDWR);
  if(testdev==-1)
  {
    printf("can't open file!\n ");
    exit(0);
  }
write(testdev,buf,50);
printf("write \"%s\"\n",buf,50);
strcpy(buf,"apple to dev! ");
printf("the buffer is changed to \"%s\"\n",buf,50);
read(testdev,buf,50);
printf("read from dev is \"%s\"\n",buf);

close(testdev);
}