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);

}