I am new to VMS. The question I have is how to call a COBOL program running on VMS from outside, say some Java application running on Linux. Can anyone give me a pointer where to look?
You will need to use the JNI (JAVA NATIVE INTERFACE)
I’ve done it with C, it is absolutely doable with COBOL
You need to understand that VMS uses descriptors .
I’d start with the VMS programming concepts manual, plus the JNI documentation for the version of JAVA you are using.
I’m currently running the X86 port of VMS and am doing everything in C (still sorting out the debugger)
Once I get this sorted out, I will be using some multithreaded processes to feed data to Python Apps running outside VMS…
if your VMS environment has working networking, why not just a simple call to ssh? e.g. system(“ssh user@vax run cobolprg”) or similar.
SSH might work, but it would depend on the application and what he is trying to do.
I’ve done it where I have written multithreaded apps on the VMS side to look for a connection and then fire off (or re-use) a thread for executing code on VMS and passing the results back to the caller.
I’d consider something similar, if multiple access is required. (Can COBOL multi-thread?) and secure the connection with SSL. If it is a single connection, then threading is not an issue and can be ignored.
The COBOL app would need to be up and running and listening for a connection. I’d run it as a detached process (not a batch job)
He will still need to understand how VMS handles variables and how it passes them.