Introduction to CL400 programming
CL400 programming is a type of programming language used for developing applications on IBM's AS/400 systems. The CL stands for "Control Language", and it is used to write programs that can manage system resources, perform system maintenance tasks, and execute other programs.
CL400 is a procedural language, meaning that it follows a specific sequence of steps to achieve a specific task. It is often used in conjunction with other languages, such as RPG and COBOL, to develop complex applications.
The basic syntax of CL400 programming is relatively straightforward, and it uses commands and parameters to instruct the system to perform specific tasks. Here is an example of a basic CL400 program:
/* Sample CL400 program */
PGM
DCL VAR(&NAME) TYPE(*CHAR) LEN(30)
DCL VAR(&AGE) TYPE(*DEC) LEN(3 0)
DCL VAR(&MESSAGE) TYPE(*CHAR) LEN(50)
CHGVAR VAR(&NAME) VALUE('John Smith')
CHGVAR VAR(&AGE) VALUE(35)
CHGVAR VAR(&MESSAGE) VALUE('Hello, ' *CAT &NAME *CAT '! You are ' *CAT &AGE *CAT ' years old.')
SNDPGMMSG MSG(&MESSAGE) TOUSR(*CURRENT)
ENDPGM
In this program, we first declare three variables using the DCL command. We then assign values to these variables using the CHGVAR command, and concatenate them together to create a message. Finally, we use the SNDPGMMSG command to send the message to the current user.
The program structure of a CL400 program typically consists of a series of commands, each with its own parameters and options. These commands are grouped together into procedures, which are identified by the PGM and ENDPGM commands. Within a procedure, commands are executed in the order in which they appear, unless conditional statements are used to control program flow.
Overall, CL400 programming provides a powerful tool for managing system resources and performing maintenance tasks on IBM's AS/400 systems. While it may not be as widely used as some other programming languages, it remains an important part of the AS/400 development toolkit.
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