NetCOBOL for SPARC Architecture SAF Subroutines User's Guide

Compilation Method
Appendix D. CGI To SAF Subroutines Conversion Guide 119
It is necessary to set the compilation option THREAD (MULTI) for creating multithread
objects.
Accessing Common Resources
A CGI application runs as one execution thread (single thread) in a dedicated process
of the CGI application itself. Thus, there are no resources shared by several threads
in a single process.
A SAF application runs as several threads (multi-threads) within the process of NES
itself. Therefore, several threads may share resources.
It is necessary to control synchronization in order to prevent competition when SAF
applications share common resources. Two types of synchronization controls are
available for resource sharing: Automatic synchronization control by the COBOL runtime
system, and synchronization control conducted by the SAF application itself
using the "thread synchronization control subroutine" supplied by COBOL.
For details, refer to the following sections in Chapter 24, Multithread Programs in the
"NetCOBOL User’s Guide."
• Resource Sharing among Threads
• Thread Synchronization Control Subroutine
Server Interface Area
Users of CGI applications need not pay particular attention to the interface with the
WWW server, with the exception of the environment variables. An SAF application is
called by the NetCOBOL SAF director initiated by NES and receives an interface
(parameter) area for transferring data with the NetCOBOL SAF director. Thus, it is
necessary to modify the LINKAGE SECTION and PROCEDURE DIVISION when
changing a CGI application into a SAF application. In addition, it is necessary to set
the address of the interface area into COBW3, which is the interface with SAF
subroutines. For example:
Contents of the CGI application
WORKING-STORAGE SECTION.
COPY COBW3.
PROCEDURE DIVISION.
MOVE LOW-VALUE TO COBW3.