In <003c01cab362$c950c0c0$5bf242...@org>, on 02/21/2010
at 06:00 PM, Charles Mills <charl...@mcn.org> said:
>Subject: Best practice for 24-bit storage in assembler called from C/C++
Best practice is for new code to be refreshable and reentrant.
>I'm writing a fairly large MVS batch application in C++. At several
>points it is necessary to call "library" type routines that I am writing
>in assembler. Several of the routines (unfortunately) need to use QSAM
>macros and so need below-the-line storage.
The issues are the same whether the storage is above the line or below.
>Obviously I could do a GETMAIN or STORAGE OBTAIN LOC=24 on the way in
>and FREEMAIN or STORAGE RELEASE on the way out.
Don't you want to leave the DCB open between calls?
>I could make the calling C++ responsible for providing a "work area"
>obtained with _malloc24(). But I don't like that for "aesthetic" reasons
>-
>violates encapsulation, making the caller responsible for the inner
>workings of the called function.
Not if that storage is a "black box".
>Is there a better way?
Does LE use a CXD to allocate a pseudo-register vector?
>Is there some "LE-supported" solution to the whole problem, such as a
>"below the line stack" feature
Unless you're closing the DCB after every call, you want it on the heap
rather than the stack.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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