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HP OpenVMS Systemsask the wizard |
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The Question is: I am using a dummy flag file to signal Pathworks 6.0a PCs that a process is up and running on my VAX. The application is written using VAXC. I have used the "fop=dlt" keyword in the open to mark the file for delete when the application closes. The file deletes when the application exits or crashes, but not when the process is stopped or the system shuts down. Is there another way to handle this or another option to let my DOS PC know that the process is up? The Answer is :
One could obviously maintain a TCP/IP or DECnet link between the
applications. Without the creation of the static object (the file),
there is no need for a cleanup.
Stopping a process is a rather harsh mechanism, and is explicitly
intended to bypass things like this cleanup operation as well as
opertions such as application exit handlers. As an alternative to
STOP (or sys$delrpc) one could use an application based on the
sys$forcex service for this task. (See below for an example of
this.)
And the system startup could locate and delete any older (node-specific)
lock files found during the system startup.
/*
** COPYRIGHT (c) 1992, 1996 BY
** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.
** ALL RIGHTS RESERVED.
**
** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED
** ONLY IN ACCORDANCE OF THE TERMS OF SUCH LICENSE AND WITH THE
** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER
** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY
** TRANSFERRED.
**
** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE
** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
** CORPORATION.
**
** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS
** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
*/
/*
**++
** Facility:
**
** Examples
**
** Version: V1.0
**
** Abstract:
**
** Performs a $FORCEX on the specified target. Set up to
** be called as a foreign command.
**
** Author:
** Steve Hoffman
**
** Creation Date: 1-Jan-1990
**
** Modification History:
**--
*/
/*
/* Example/test program that performs a $FORCEX on the specified
/* process. Called as a foreign command, with one argument, the
/* hexidecimal PID of the target process. May require GROUP or
/* WORLD privilege.
*/
#include <ssdef.h>
#include <starlet.h>
#include <stdio.h>
main( int argc, char **argv )
{
unsigned long int retstat;
unsigned long int pid;
unsigned long int finalstat = SS$_BUGCHECK;
char hex[12];
if (( argc != 2 ) && ( argc != 3 ))
{
printf("this is a foreign command; usage: fx pid exitstat\n");
return SS$_BADPARAM;
}
sscanf( argv[1], "%x", &pid );
if ( argc == 3 )
sscanf( argv[1], "%x", &finalstat );
retstat = sys$forcex( &pid, 0, finalstat );
return retstat;
}
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