linux c实现文件复制

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include <libgen.h>
#include <fcntl.h>
#define BUFFER_SIZE 4096
int main(int argc,char* argv[])
{

   if(argc != 3)
   {
      printf("Usage:%s src dest\n",basename(argv[0]));
      exit(-1);
   }
   char* szSrc = argv[1];
   char* szDest = argv[2];
   
   if(access(szSrc,F_OK)!=0)
   printf("file is not exists.\n"),exit(-1);
   
   int srcfd = open(szSrc,O_RDWR);
   
   if(srcfd == -1)
     perror("open"),exit(-1);
   
   int destfd = open(szDest,O_RDWR|O_CREAT|O_TRUNC,0664);
   if(destfd == -1)
     perror("open"),exit(-1);
   ssize_t size = -1;
   char buf[BUFFER_SIZE];
   while((size=read(srcfd,buf,4096)))
     write(destfd,buf,size);
   printf("%s cp to %s success!\n",szSrc,szDest);
   return 0;  
}