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Warning with extern "C" blocks

+2 votes
349 views

I tried using -Wzero-as-null-pointer-constant in a C++ program, but I got warnings in some C headers, even though they are wrapped in extern "C" blocks.

Since there is no nullptr in C, wouldn't it make more sense to disable the warning within those blocks? Is there some option that I'm missing?

posted Oct 13, 2014 by anonymous

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1 Answer

+1 vote

Although it's usually used in headers that need to be valid in both C and C++, extern "C" does not mean you can't use C++ features.

extern "C" {
 void* ptr = nullptr;
}
answer Oct 13, 2014 by Gurminder
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Warning for incompatible functions declared 'extern "C"'?

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// Intended to be a helper function not exposed from library
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Obviously the GetEngineVersion function cannot have C linkage because it returns a C++ class.

My question is: does GCC have a warning for this scenario? Specifically, can it warn when something is declared extern "C" that's incompatible with C linkage?

I compile with the following warning flags and I didn't get a warning:

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...