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 ltqdput 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 zltstore 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 the calling

 

program by giving the options “-lzcom_c -lpthread” to cc(1) or ld(1).

Threads

This routine may be called from a multi-threaded application using the

Considerations

POSIX (1003.1c) kernel threads API package. This routine has the

 

following characteristics when called by a multi-threaded application:

 

cancellation point

Thread cancellation can occur when a thread

 

 

 

calls this routine.

Chapter 4

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