Reference Guide

ZCOM C I/F Library Routines
ZCLOS (3X)
Chapter 4168
ZCLOS (3X)
NAME zclos - Delete program input ZLU
SYNOPSIS
#include <zcom/zcomsys.h>
#include <zcom/zcomcall.h> /* if compiled with ANSI C (recommended) */
int32 zclos (zap)
zaddr_type *zap;
DESCRIPTION Routine zclos closes the program ZLU set up by the zopen call and
returns the ZLU back to the system for reuse. This call should normally
always occur before a program terminates. If the program ZLU is not
closed, then the ZCOM subsystem will continue to hold all of the
resources associated with the ZLU and may add messages to the input
queue. This feature allows a program to open a ZLU on another
program’s behalf, or to be killed and rerun without losing any queued
messages. It is the programmer’s responsibility to ensure that all
unnecessary program ZLUs are closed before the program terminates.
If zclos is called to close a program’s primary ZLU, the program will no
longer have a primary ZLU. Usually, a program should open another
ZLU as the primary ZLU because some APIs may return an error if the
primary ZLU does not exist (e.g. zsend(3X)).
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
Considerations
This routine may be called from multi-threaded application using the
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.
async-cancel unsafe The calling thread’s cancelability type must be
PTHREAD_CANCEL_DEFERRED if
cancellation is enabled.