#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
 
int main()
{
        int file=0;
        if((file=open("testfile.txt",O_RDONLY)) < -1)
                return 1;
 
        char buffer[19];
        if(read(file,buffer,19) != 19)  return 1;
        printf("%s\n",buffer);
 
        if(lseek(file,10,SEEK_SET) < 0) return 1;
 
        if(read(file,buffer,19) != 19)  return 1;
        printf("%s\n",buffer);
 
        return 0;
}