RSC/MP 7.2 Programming Manual

Application Design
HP NonStop Remote Server Call (RSC/MP) Programming Manual—522360-004
5-5
UNIX Signal Handling
UNIX Signal Handling
The RSC/MP UNIX library does not process UNIX signals. Therefore, all signals will
cause the application’s signal handler to be entered. The user program must protect
against reentry into the RSC/MP library as a part of signal processing. Also, if a fatal
signal is received, the application should initiate a cleanup of the RSC/MP resources it
has in use.
Application Persistence
To ensure that an application can recover from failures consider:
•
Setting up a backup TDP that takes over upon failure of the primary process.
•
Logging errors.
•
Informing system users that a communications failure has occurred, that recovery
is in progress, and failure recovery is completed.
See Persistent Applications on page 6-15, for more information about developing a
persistent application.
Using Multiple Applications and Connections
on a Workstation
Your application can be run on a workstation with other applications written by other
users who have no knowledge of your application. When designing your applications
consider:
•
The first RSC/MP connection you issue on a workstation to a host system causes
the transport layer to establish a connection through the physical resource and
causes Pipeman to open a logical pipe for communications between RSCPIPE on
the workstation and the TDP on the host system.
•
Each subsequent RSC/MP connection you issue from a workstation to a host
system with which it already has an active connection causes Pipeman to open a
new logical pipe that is multiplexed on the existing network connection.
•
Through an application (or multiple applications) on a workstation you can connect
to different TDPs on the same host system or to TDPs on different host systems by
using a single RSCPIPE process, a single Pipeman process, and (depending on
your configuration) one or more NIF processes. See the Remote Server Call
(RSC/MP) Installation and Configuration Guide for information about configuration.
•
The physical network connection remains established for a configurable length of
time after you disconnected all RSC/MP connections on the workstation.
•
The first RSC/MP connection you issue on a workstation starts the RSCPIPE
process (if it is not already running) under the name you specified in the
SUBSYSTEM_NAME option. If you change the value of SUBSYSTEM_NAME