CRE Programmer's Guide

CRE Services
Common Run-Time Environment (CRE) Programmer’s Guide—528146-004
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$RECEIVE
modules to share standard files (standard out and standard log) that write to spooler
collectors.
In the OSS environment, the file system supports standard files—the CRE, therefore,
does not provide such support. Language-specific run-time libraries call OSS routines
to access standard files. Because the CRE does not support standard files in the OSS
environment, it does not support the CRE routines for sharing spooled files.
$RECEIVE
$RECEIVE is supported in both the TNS and native CRE environments. In the
Guardian and OSS environments, programs receive the following types of messages
from $RECEIVE: system messages and messages sent by other processes. In the
Guardian environment, processes also receive initialization messages (startup
message, ASSIGN messages, and PARAM message) from $RECEIVE. Processes
running in the OSS environment do not receive initialization messages from
$RECEIVE.
Memory Organization
The CRE manages a user heap for programs running in either the OSS or Guardian
environments.
For a given heap size, a program running in the OSS environment might have a
different amount of available space than the same program running in the Guardian
environment.
Traps and Exceptions
For Guardian processes running in the TNS environment, the CRE enables a trap
handler during program initialization and manages exception handling during program
execution. Programs can use the Guardian ARMTRAP procedure to detect and
process exceptions.
Guardian C programs use the signal feature to detect exceptions, rather than traps.
In the native environment, traps are replaced with signals.
For Guardian processes running in the native environment, the CRE provides a default
signal handler for all signals whose default action is not signal ignore [SIGIGN]. The
signal handler takes all appropriate actions, then terminates the process. The signal
handler does not return control to its caller. Refer to the Guardian Programmer’s Guide
for more information on signals.
The OSS environment supports signals but does not support trap handlers. Therefore,
the CRE does not regain control of a process if an exception occurs. In most cases,
the OSS environment makes error information available to running programs. The CRE
does not provide a signal handler for OSS processes. See the OSS Programmer’s
Guide for more information about exception handling in the OSS environment.