ACC Programmer's Reference Guide

ZCOM C I/F Library Routines
ZPEEK (3X)
Chapter 4274
ZPEEK (3X)
NAME zpeek – Read data from ZLU without disturbing input queue
SYNOPSIS
#include <zcom/zcomsys.h>
#include <zcom/zcomcall.h> /* if compiled with ANSI C (recommended) */
int32 zpeek (zap, mode, mhp, ibuf, len, rlen, rstat)
zaddr_type *zap;
uint32 mode;
zmhd_type *mhp;
char *ibuf;
int32 len;
int32 *rlen;
int32 *rstat;
DESCRIPTION Routine zpeek fetches the next message from the head of a program ZLU
input queue. The program has the option to wait (i.e. suspend) if there is
no data on the queue specified. The actual length of the data message is
returned in rlen.
zpeek is similar to zread(3X) except that it does not remove the message
after retrieving it. Multiple calls to zpeek on the same ZLU will return
the same message until zread(3X) is called, i.e. it can only look at the
first message on the input queue. In addition, the automatic response
mechanism is not triggered when fetching a message by zpeek, i.e. no
response will be sent to the message sender until the message is removed
from the input queue with zread.
The zpeek routine has identical parameters to the zread routine. See the
zread routine for a description of the parameters.
The libraries libzcom_c.a and libpthread.a must be linked into the calling
program by giving the options “-lzcom_c -lpthread” to cc(1) or ld(1).