writen.c

linux下的聊天程序

/* include writen */
//#include	"unp.h"
#include <stdio.h> 
#include <stdlib.h> 
#include <errno.h> 
#include <string.h> 
#include <sys/types.h> 
#include <netinet/in.h> 
#include <sys/socket.h> 
#include <sys/wait.h> 

#define SERV_PORT 9877 
#define LISTENQ 1024 
#define MAXLINE 4096 
#define SA struct sockaddr

/* Write "n" bytes to a descriptor. */
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)) <= 0) {
			if (errno == EINTR)
				nwritten = 0;	/* and call write() again */
			else
				return(-1);			/* error */
		}

		nleft -= nwritten;
		ptr   += nwritten;
	}
	return(n);
}
/* end writen */

void
Writen(int fd, void *ptr, size_t nbytes)
{
	if (writen(fd, ptr, nbytes) != nbytes)
		err_sys("writen error");
}