Suppressing: "#warning is language extension"

Question

In an xcode4.5 project I have turned on pedantic warnings. But this now gives me a warning about using #warning:

Lexical preprocessor issue
#warning is language extension

Firstly, I'd like to know why this is happening and how to stop it (with out removing the #warning).

Answer 1

trojanfoe answered why the issue was emitted (+1).

A more portable and language-compliant way to emit your warning message is:

#pragma message("YOUR WARNING HERE")

Clang will emit one warning (specifically, the one you wrote in the message -- not the pedantic one), and it appears in Xcode's issues.

Answer 2

The reason it's being generated is because #warning is an extension to the ISO standard and that is what -pedantic is about.

It looks like only a #pragma will turn it off as no -Wno-xxx flags appear available for language extensions.

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-pedantic"

#warning blah blah blah

#pragma clang diagnostic pop