CRE Programmer's Guide

CRE Services
Common Run-Time Environment (CRE) Programmer’s Guide—528146-004
2-6
Process Pairs
The Saved Message Utility (SMU) functions of the Common Language Utility (CLU)
library are available only in the Guardian environment.
The native CRE library does not support CLU library functions that locate and identify
file connectors.
Process Pairs
The term process pairs refers to the use of primary and backup processes in fault-
tolerant programming. In the Guardian environment, both the TNS and native CRE can
manage the backup process on behalf of the running program.
The OSS environment does not support process pairs (primary and backup).
Therefore, all CRE services and functions associated with process pairs are undefined
in the OSS environment.
Writing TAL Routines That Use the TNS CRE
Unlike C, COBOL, and FORTRAN routines, TAL routines must call TNS CRE functions
explicitly to access TNS CRE services because the TAL run-time library does not
support file I/O, math, or string functions. This subsection describes considerations for
TAL routines that run in the TNS CRE in the Guardian environment.
Follow these guidelines to write TAL routines that run in the TNS CRE:
•
Use a TAL ENV directive to establish the correct environment for your TAL
programs. A TAL program can run in the TNS CRE if the TAL main routine has the
ENV COMMON attribute and other TNS CRE requirements are met. Section 3,
Compiling and Binding Programs for the TNS CRE, describes the TAL ENV
directive. See also the TAL Reference Manual.
•
Do not manipulate directly the upper 32K of the user data segment. The TNS CRE
uses this space to store its data objects. Do not use memory addresses G[0] or
G[1].
•
Do not directly manipulate program resources that are likely to be shared with
other languages.
Process initialization Yes Yes
Process termination Yes Yes
Process pairs No No
Note. All CRE service functions are visible to all programs in the Guardian and OSS
environments. The results of calling a function that is not defined in the current environment,
however, are undefined.
Table 2-2. CRE Services in the OSS Environment (page 2 of 2)
Service TNS environment Native environment