函数名: lseek 
 功  能: 移动文件读/写指针 
 用  法: #include <io.h> 
         long lseek(int handle, long offset, int fromwhere); 
 程序例: 
#include <sys\stat.h> 
 #include <string.h> 
 #include <stdio.h> 
 #include <fcntl.h> 
 #include <io.h> 
int main(void) 
 { 
    int handle; 
    char msg[] = "This is a test"; 
    char ch; 
   /* create a file */ 
    handle = open("TEST.$$$", O_CREAT | O_RDWR, S_IREAD | S_IWRITE); 
   /* write some data to the file */ 
    write(handle, msg, strlen(msg)); 
   /* seek to the begining of the file */ 
    lseek(handle, 0L, SEEK_SET); 
   /* reads chars from the file until we hit EOF */ 
    do 
    { 
       read(handle, &ch, 1); 
       printf("%c", ch); 
    }  while (!eof(handle)); 
   close(handle); 
    return 0; 
 }