ACC Programmer's Reference Guide

144 Chapter4
ZCOM C I/F Library Routines
LTQDGET (3X)
LTQDGET (3X)
NAME
ltqdget – Retrieve data buffer in terminal data queue
SYNOPSIS
#include <zcom/zcomsys.h>
#include <zcom/zcomcall.h> /* if compiled with ANSI C (recommended) */
int32 ltqdget (zap, queue, ibuf, len, rlenp)
zaddr_type *zap;
uint32 queue;
char *ibuf;
int32 len;
int32 *rlenp;
DESCRIPTION
Routine ltqdget retrieves the data message stored in the data queue of
the logical terminal tables. It returns the first message in the specified
queue and releases the buffers back to the ZCOM subsystem free data
buffer pool. See the man page for lt qdput on how to store a message in
the data queue.
The data queue is designed to store a relatively large or unpredictable
amount of terminal data in a FIFO order. When compared to logical data
storage (refer to zl tstore and zltup), the data queues allow terminal data
to be stored dynamically, that is, memory is used only when data is
stored. However, it is penalized by incurring more processing overhead in
data update and retrieval. In addition, access is restricted to a FIFO
order.
The libraries libzcom_c.a and libpthread.a must be linked into thecalling
program by giving the options “-lzcom_c -lpthread” to cc(1) or ld(1).