rwn.c

来自「一个不错的GA-NN的神经网络模型的示范代码。适合入门学习」· C语言 代码 · 共 69 行

/*	rwn.c */
/* 	Copyright 2004 Oswaldo Morizaki */
/*  The readn() and writen() functions were taken from the book 
				"Advanced Programming in the UNIX* Environment" by W. Richard Stevens copy 1993 */

/* 	This file is part of ga-nn-ag.

    ga-nn-ag is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    ga-nn-ag is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with ga-nn-ag; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/


#include "my_header.h"

ssize_t writen(int fd, const void *vptr, size_t n)
{
	size_t	nleft;
	ssize_t	nwritten;
	const char *ptr;
	
	ptr = vptr;
	nleft = n;
	while (nleft > 0)
	{
		if ( (nwritten = write(fd, ptr, nleft)) < 1)
		{
			return(nwritten);
		}
		nleft -= nwritten;
		ptr   += nwritten;
	}
	return(n);
}

ssize_t readn(int fd, void *vptr, size_t n)
{
	size_t	nleft;
	ssize_t	nread;
	char *ptr;

	ptr = vptr;
	nleft = n;
	while (nleft > 0)
	{
		if ( (nread = read(fd, ptr, nleft)) < 0)
		{
			return(nread);
		}
		else if (nread == 0)
		{
			break;
		}
		nleft -= nread;
		ptr 		+= nread;
	}
	return(n - nleft);
}