31548 - [patch] The define of NS_DEBUG gives me a compilation warning.

Status: VERIFIED WONTFIX

(Core :: XPCOM, defect, P3)

Description

[Jonas Utterstrom]

In my application, I have both NS_DEBUG and DEBUG define. This gives a
compilation warning when I've included nsDebug.h. So please have a look at the
patch I have attached to this bug.

Comment 1

[Jonas Utterstrom]

Attachment: Patch to remove some warnings when NS_DEBUG is already defined.

Comment 2

[Suresh Duddi (gone)]

Yeah your patch looks ok.

Considering that nsDebug.h is the one defining NS_DEBUG, I would like to know 
how we can end up with a warning of multiple define.

Can you explain how it is happening ?

Comment 3

[Jonas Utterstrom]

Well, it doesn't occur in Mozilla. But in my own applications that use the
Mozilla libraries I have to define NS_DEBUG due to the design of nsCOMPtr.
http://lxr.mozilla.org/seamonkey/source/xpcom/base/nsCOMPtr.h#98
Otherwise I will get link errors when using nsCOMPtr in my application. But some
of my code also defines DEBUG, which gives this annoying warning. 

And an extra ifdef guard wouldn't do any harm?

Comment 4

[Suresh Duddi (gone)]

Yeah it is harmless. But usually these errors of multiple defines point in the
direction of incorrect usage. Hence my curiosity.

nsCOMPtr.h includes nsDebug.h  So if nsDebug.h defined NS_DEBUG in the first
place, things should be just fine.

Instead of defining NS_DEBUG, if you just define DEBUG either in a base header
file or in your build process as we do in mozilla, you should be fine. Right ?

Comment 5

[Jonas Utterstrom]

I settle with DEBUG for now, but I think it's a too common used define.  I think
that before Mozilla is released something must be done to nsCOMPtr.h so that I
can use the Mozilla release libraries with my debug build application. And of
course the other way around.

Comment 6

[Suresh Duddi (gone)]

Now that is a damn good suggestion. I will say wont fix and file a separate bug 
on that. ok ?

Comment 7

[leger]

Adding verifyme keyword.

Comment 8

[leger]

Marking Verified per dp's last comments.