Timers in COBOL

Our example demonstrates how to use timers in COBOL. While COBOL doesn’t have built-in timer functionality like some modern languages, we can simulate timers using the CALL statement and the system’s sleep function.

IDENTIFICATION DIVISION.
PROGRAM-ID. TIMERS-EXAMPLE.

ENVIRONMENT DIVISION.
CONFIGURATION SECTION.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-SLEEP-SECONDS PIC 9(4) COMP.

PROCEDURE DIVISION.
MAIN-PROCEDURE.
    DISPLAY "Starting timer example...".

    * Simulate a timer that waits for 2 seconds
    MOVE 2 TO WS-SLEEP-SECONDS.
    CALL "C$SLEEP" USING WS-SLEEP-SECONDS.
    DISPLAY "Timer 1 fired".

    * Simulate a second timer
    MOVE 1 TO WS-SLEEP-SECONDS.
    CALL "C$SLEEP" USING WS-SLEEP-SECONDS.
    DISPLAY "Timer 2 fired".

    STOP RUN.

In this COBOL program:

1. We define a variable WS-SLEEP-SECONDS to hold the number of seconds we want to wait.

2. We use the CALL statement to invoke the C$SLEEP function, which is a common extension in many COBOL compilers that allows the program to pause for a specified number of seconds.

3. Our first “timer” waits for 2 seconds, then displays a message.

4. Our second “timer” waits for 1 second, then displays a message.

Note that COBOL doesn’t have native support for asynchronous operations or cancelling timers like in the original example. The timers here execute sequentially, and we can’t stop them once started.

To run this program:

1. Save the code in a file with a .cbl extension, for example timers.cbl.
2. Compile the program using your COBOL compiler.
3. Run the compiled program.

The output should look something like this:

Starting timer example...
Timer 1 fired
Timer 2 fired

This example demonstrates a basic way to implement timed operations in COBOL. For more complex timing needs, you might need to use system-specific calls or external libraries, depending on your COBOL environment and requirements.