/*
 * This function writes n bytes to the file 
 * specified by descriptor fd copying them from 
 * the memory area addressed by buf.
 */

#include <unistd.h>

ssize_t
write(int fd, const void *buf, size_t n)
{
    /*
     *   - Check that fd is a valid descriptor
     */

    /*
     *   - Check that buf points to a valid memory area
     */

    /*
     *   - Check that n is a non-negative number
     */

    /*
     *   - Attempt to write the requested number of bytes
     */

    /*
     *   - Return number of bytes actually written, -1 in 
     *   case of error.
     */

}