Comments on: Gem #70: The Scope Locks Idiom

By: Pat Rogers

Pat Rogers — Thu, 04 Aug 2011 22:45:17 +0000

Matt,

Yes indeed!

Thanks for the note.

By: Matt

Matt — Thu, 04 Aug 2011 19:04:48 +0000

Just a side note here, pragma Unreferenced and Unreferenced_Objects can be useful to prevent unneeded compiler warnings when such types are used.

By: Pat Rogers

Pat Rogers — Fri, 02 Oct 2009 04:10:14 +0000

Christoph,

There is no requirement to make it visibly tagged in this specific case. Just a matter of habit.

Thanks for the question!

By: Christoph Grein

Christoph Grein — Thu, 01 Oct 2009 13:26:59 +0000

Pat,
is there any reson why you make Scope_Lock visibly tagged?

By: Pat Rogers

Pat Rogers — Wed, 30 Sep 2009 17:55:33 +0000

Jeff,

I changed the code too soon. Since the type is limited there will only be one compiler-generated call to Finalize, and since it is not visibly controlled the clients cannot call Finalize themselves. Hence there is no need for the protection against multiple calls after all.

Thanks again for the comment!

By: Pat Rogers

Pat Rogers — Wed, 23 Sep 2009 18:06:41 +0000

Yes, same idea.

Your test for multiple calls to Finalize is an important improvement that I will add to the gem code. Thanks for the comment!

By: Jeff

Jeff — Wed, 23 Sep 2009 16:41:24 +0000

See PragmARC.Safe_Semaphore_Handler, released 2000 May 01, for an implementation of this (in Ada 95).

http://pragmada.x10hosting.com/