文件复制

#include <unistd.h>

#include <stdlib.h>

#include <sys/stat.h>

#include  <fcntl.h>

int main()

{

    char c;

    int in,out;

   in=open("file.in",O_RDONLY);

   out=open("file.out",O_WRONLY|O_CREAT,S_IRUSR|S_IWUSR);

   while(read(in,&c,1)==1)

       write(out,&c,1);

   exit(0);

}
//速度1kB

int main()

{

    char c[1024];

    int in,out;

    int nread;

   in=open("file.in",O_RDONLY);

   out=open("file.out",O_WRONLY|O_CREAT,S_IRUSR|S_IWUSR);

   while((nread=read(in,c,sizeof(c)))>0)

       write(out,c,nread);

   exit(0);

}