Re: Native way to lock an object in RPG?

On Aug 25, 2016, at 1:32 PM, Bob Cagle <bcagle@xxxxxxxxxxx> wrote:

Yes, maybe I shouldn't have said 'native'. I'm perfectly fine with accessing either a CLLE or another service program to access the function. I was just curious if there was a %BIF or RPG opcode that I was missing - doesn't sound like it though.

The reason for wanting to attempt the lock is I have a process that cannot run while another process is running. This other process puts a lock on a specific data area. I just need to check if that data area is locked or not before allowing my process to continue.

-----Original Message-----
From: Mark S Waterbury


Bob:

What do you mean by "native"? On OS/400 and IBM i, you can not get much more "native" than invoking MI (machine interface) instructions directly from within ILE programs as built-in functions.

What kind(s) of object type(s) are you wanting to "lock"? And for what purpose(s)?

Here is one way to accomplish this:

Create a CLP *PGM or CLLE procedure you can call from RPG, that issues the ALCOBJ command to "lock" an object, and uses MONMSG CPF1002 to detect if the object could not be allocated; specify WAIT(0) on the ALCOBJ command so it does not wait for the lock, but if the object cannot immediately be "allocated" (locked), the command signals an exception by throwing an *ESCAPE message CPF1002. Then, your CL program or procedure can return some kind of "return code" to indicate success or failure.

IMHO, using CL commands and a CLP program or CLLE program or procedure in this way is still considered "native." :-)

HTH,

Mark S.Waterbury
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