简单实现C语言copy命令

#include 
#include 
#include 
#include 
#include 
#include 
#define DATA_SIZE 30
int my_copy(int argc,char **argv);
int main(int argc,char **argv)
{
        my_copy(argc,argv);
        return 0;
}
// ./my_copy dest.txt src.txt
int my_copy(int argc,char **argv)
{

        int fd_src,fd_dest;
        char buf[DATA_SIZE];
        int count = 0;
        if(argc != 3 ) {

                perror("input error");
                return -1;
        }
        fd_src = open(argv[2],O_RDONLY);
        if(fd_src == -1){
                perror("open failed");
                return -1;
        }

        fd_dest = open(argv[1],O_WRONLY | O_CREAT | O_EXCL,0700);
        if(fd_dest == -1){

                close(fd_src);
                perror("open failed");
                return -1;
        }
        while(1){
                count = read(fd_src,buf,DATA_SIZE);
                if(count == -1 ) {
                        perror("read failed");
                        return -1;
                }
                if(count == 0) break;
                write(fd_dest,buf,count)；
        }
        close(fd_src);
        close(fd_dest);
}