Signals in COBOL

Here’s the translation of the Go code to COBOL, formatted in Markdown suitable for Hugo:

Our program demonstrates how to handle signals in COBOL. In this example, we’ll show how to gracefully handle interrupts.

       IDENTIFICATION DIVISION.
       PROGRAM-ID. HANDLE-SIGNALS.
       ENVIRONMENT DIVISION.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-SIGNAL-STATUS PIC 9 VALUE 0.
          88 WS-SIGNAL-RECEIVED VALUE 1.
       
       PROCEDURE DIVISION.
       MAIN-PROCEDURE.
           DISPLAY "Awaiting signal"
           PERFORM HANDLE-SIGNALS
           DISPLAY "Exiting"
           STOP RUN.

       HANDLE-SIGNALS.
           CALL "CBL_OC_NANOSLEEP" USING BY VALUE 1000000000
           ON EXCEPTION
               SET WS-SIGNAL-RECEIVED TO TRUE
           END-CALL
           IF WS-SIGNAL-RECEIVED
               DISPLAY X"0A" "Interrupt received"
           ELSE
               GO TO HANDLE-SIGNALS
           END-IF.

In COBOL, we don’t have built-in signal handling mechanisms like in more modern languages. However, we can simulate a similar behavior using the CBL_OC_NANOSLEEP function, which can be interrupted by a signal.

The program starts by displaying “Awaiting signal”. It then enters a loop in the HANDLE-SIGNALS paragraph, where it sleeps for 1 second (1,000,000,000 nanoseconds) using CBL_OC_NANOSLEEP. If this call is interrupted (for example, by pressing Ctrl+C), it will raise an exception.

When an exception occurs (simulating a signal receipt), we set WS-SIGNAL-RECEIVED to TRUE, print a newline (X"0A") followed by “Interrupt received”, and exit the loop. If no exception occurs, the program continues to loop.

After the loop ends, the program displays “Exiting” and terminates.

To run this program, you would compile it with a COBOL compiler and then execute the resulting binary. The exact commands may vary depending on your COBOL implementation, but it might look something like this:

$ cobc -x handle_signals.cob
$ ./handle_signals
Awaiting signal
^C
Interrupt received
Exiting

In this example, ‘^C’ represents pressing Ctrl+C to send an interrupt signal.

Note that this is a simplified simulation of signal handling in COBOL. In real-world applications, more robust error handling and system-specific considerations would be necessary.