FAQ-0530 How do I use the cleanup stack with R and M classes?


FAQ-0530 How do I use the cleanup stack with R and M classes?

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Classification:	C++	Category:	Base
Created:	10/19/2000	Modified:	09/11/2002
Number:	FAQ-0530
Platform:	Not Applicable

Question:
If I've an instance or a pointer to an R or M class, but it's not a member of the current class, I'll want their resources to be cleaned up if there's a Leave.
R classes typically need a Close() call.
M classes typically need a Release() call.

Answer:
The template functions CleanupDeletePushL(), CleanupClosePushL() and CleanupReleasePushL() push cleanup items onto the cleanup stack which cause the appropriate item to be called. They are declared in S32STRM.H.

E.g.
RFile& aFile; CleanupClosePushL(aFile);

To save code size some M classes define their own PushL and Pop functions which do this for you. E.g. RReadStream, RWriteStream, MStreamBuf.