senderr.c

unix环境高级编程一书源代码 本书全面介绍了UNIX系统的程序设计界面—系统调用界面和标准C库提供的许多函数。 本书的前15章着重于理论知识的阐述

#include	"ourhdr.h"

/* Used when we had planned to send an fd using send_fd(),
 * but encountered an error instead.  We send the error back
 * using the send_fd()/recv_fd() protocol. */

int
send_err(int clifd, int errcode, const char *msg)
{
	int		n;

	if ( (n = strlen(msg)) > 0)
		if (writen(clifd, msg, n) != n)	/* send the error message */
			return(-1);

	if (errcode >= 0)
		errcode = -1;	/* must be negative */

	if (send_fd(clifd, errcode) < 0)
		return(-1);

	return(0);
}