tcp_comm.c

Unix/Linux下服务端/客户通过TCP/IP通讯的程序

#include "tcp.h"

int readn( fd, ptr, nbytes )
register int fd;
char *ptr;
int nbytes;
{
	int nleft, nread;
	nleft = nbytes;	
	while( nleft > 0 ){
		nread = read( fd, ptr, nleft ) ;
		if ( nread < 0 ) 
			return ( nread );
		else if ( nread == 0 ) break;
		nleft -= nread;
		ptr += nread ;
	}
	return( nbytes - nleft );
}

int writen( fd, ptr, nbytes )
register int fd;
char *ptr;
int nbytes;
{
	int nleft, nwritten;
	nleft = nbytes;	
	while( nleft > 0 ) {
		nwritten = write( fd, ptr, nleft );
		if ( nwritten <= 0 ) 
			return ( nwritten );
		nleft -= nwritten ;
		ptr += nwritten;
	}
	return ( nbytes - nleft );
}

int readline ( fd, ptr, maxlen ) 
register int fd;
char *ptr ;
int maxlen;
{
	int n, rc;
	char c;
	for ( n = 1; n<maxlen;n++){
		if ( ( rc = read( fd, &c, 1 )) == 1 ) {
			*ptr++=c;
			if ( c=='\n')
				break;
		}
		else if ( rc == 0 ) {
			if ( n == 1 ) return(0);
			else break;
		}
		else return(-1);
	}
	*ptr = '\0';
	return (n);
}