804872 - xpcom/tests/TestObserverArray.cpp uses a C99 extension, causing a clang warning, triggering a -Werror build failure

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Jeff Walden [:Waldo]]

Attachment: Patch

Empty macro arguments, like so:

#define FOO(x, y) bar
FOO(1, )

are only valid in C99 and C++11.

http://stackoverflow.com/questions/7666344/are-empty-macro-arguments-legal-in-c11

TestObserverArray.cpp compiles with no special options, so it compiles as C++98.  clang r163985 warns about using a C99/C++11 extension here, and since the directory's FAIL_ON_WARNINGS = 1, this breaks the build.

Comment 1

[Daniel Holbert [:dholbert]]

Comment on attachment 674483 [details] [diff] [review]
Patch

The ";" in the middle of a line is a little bizarre there, readability-wise.  (I actually didn't even see it at first -- couldn't tell what the patch was changing -- and even after seeing it, it's a little bizarre.)

Perhaps "{}" would be better, as an "execute no code" marker?

Either way, r=me.

Comment 2

[Jeff Walden [:Waldo]]

{} was a better call than ;.  I added a /* nothing */ to make it even more visible, and not something that potentially might look like a literal or something.

https://hg.mozilla.org/integration/mozilla-inbound/rev/fae81f4e7a9b

Comment 3

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/fae81f4e7a9b