Contents
Figures . . . . . . . . . . . . . . vii
Tables . . . . . . . . . . . . . . .ix
About this book . . . . . . . . . . .xi
Who should read this book . . . . . . . . .xi
Document organization . . . . . . . . . .xi
How to send your comments . . . . . . . . xii
Conventions used in this book . . . . . . . . xii
Part 1. Writing applications . . . . .1
Chapter 1. Introduction to CICS
application programming . . . . . . .3
What does CICS do for you? . . . . . . . . .3
CICS transaction processing . . . . . . . . .3
The CICS family . . . . . . . . . . . .3
Transaction processing terms and concepts . . .4
Distributed transaction processing . . . . . .5
Developing applications within CICS . . . . .5
Developing client/server applications . . . . .7
How CICS runs your transactions . . . . . . .8
Components of the CICS runtime system . . . .9
How CICS executes your transactions . . . .10
The CICS application programming interface (API) 11
How to split the program logic . . . . . . .11
Summary of API presentation services . . . .12
Summary of API data services . . . . . . .13
Summary of API business logic . . . . . . .14
Summary of API problem determination logic . .16
CICS application development tools . . . . . .16
Presentation interface development . . . . .16
Application program translation . . . . . .16
Application program debugging . . . . . .17
Summary of commands used in application
development . . . . . . . . . . . . .18
Summary of CICS-supplied transactions used in
application development . . . . . . . . .18
A sample transaction . . . . . . . . . . .20
Prerequisites for the “Hello World” transaction 20
To create a “Hello World” application . . . .20
To run the “Hello World” transaction . . . . .20
Chapter 2. CICS application design
considerations . . . . . . . . . . .21
CICS transaction design efficiency considerations . .21
CICS program design efficiency considerations . .22
Shareable, loadable, and executable operating
system objects . . . . . . . . . . . .22
EXEC CICS LINK and EXEC CICS XCTL
commands . . . . . . . . . . . . . .23
COBOL PERFORM and CALL commands . . .24
C program function calls and single executable
objects . . . . . . . . . . . . . . .24
C++ object oriented design . . . . . . . .24
Internal and external procedures and functions in
PL/I programs . . . . . . . . . . . .25
Transaction data storage considerations . . . . .25
Storing data within a transaction . . . . . .26
Sharing data across transactions . . . . . .27
Data management storage considerations . . . .31
Issues affecting your data management storage
decisions . . . . . . . . . . . . . .32
CICS environment efficiency considerations . . .37
Wait conditions . . . . . . . . . . . .37
Auxiliary trace . . . . . . . . . . . .37
The NOSUSPEND option . . . . . . . . .37
Access permissions for maps and transaction
programs . . . . . . . . . . . . . .38
CICS command LENGTH operand . . . . .38
Efficiency issues for CICS locking functions . . .38
Implicit locking on nonrecoverable and
recoverable files . . . . . . . . . . . .39
Implicit locking on logically recoverable transient
data queues . . . . . . . . . . . . .41
Implicit locking on recoverable temporary
storage queues . . . . . . . . . . . .41
Explicit locking (by the application programmer) 42
Performance considerations for CICS developers . .42
Improving performance of CICS application
programs . . . . . . . . . . . . . .42
Improving performance of database access . . .46
Improving performance of DB2 file management 47
Improving performance of Oracle file
management . . . . . . . . . . . . .47
Using CICS with WebSphere MQ . . . . . . .47
Chapter 3. Programming constraints 49
General programming considerations . . . . . .49
Tabs in map and program sources . . . . . .49
The use of operating system functions . . . .49
Names reserved for CICS . . . . . . . . .49
Thread safety . . . . . . . . . . . . .50
CICS-safe functions . . . . . . . . . . .50
Using the COBOL compilers . . . . . . . . .51
Default options in EXEC CICS commands for
COBOL . . . . . . . . . . . . . . .51
Data declarations needed in COBOL . . . . .52
COBOL program invocation environment (Micro
Focus Server Express COBOL only) On CICS on
Open Systems only . . . . . . . . . . .53
COBOL program invocation environment (IBM
COBOL only) . . . . . . . . . . . . .53
Calling programs from COBOL . . . . . . .53
Working storage . . . . . . . . . . . .55
Recursion . . . . . . . . . . . . . .55
Available memory (Micro Focus Server Express
COBOL On CICS on Open Systems only) . . .55
Mixing languages . . . . . . . . . . .55
© Copyright IBM Corp. 1999, 2006 iii
