CODEWITHSUNDEEP
cgccc-preprocessorpreprocessor-directive
Thomas Erker
Thomas Erker

Reputation: 348

Disable #warning just for one header

In C/C++ code I try to port, a deprecated system header is included:

From the header:

#ifdef __GNUC__
#warning "this header is deprecated"
#endif

As we compile here with gcc -Wall -Werror, compilation stops. In the long run, replacing the use of deprecated functions is best, but for now I want to disable just this warning.

Compiling without -Werror of course works, but as this is part of a completely automated build process, I prefer not to do that.

Including the header with #undefing __GNUC__ before and #defineing it afterwards is a possibility, but I'm worried of the side effects inside the included header.

Is there a way to either disable #warning or relax -Werror just for one header?

Upvotes: 8

Views: 1407

Answers (2)

Simon Gibbons
Simon Gibbons

Reputation: 7194

You can do this with a (GCC specific) diagnostic pragma

If you surround the include with the following it will disable any warnings caused by #warning.

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcpp"
#include "header.h"
#pragma GCC diagnostic pop

Note that if you change the ignored to warning in the above the compiler still prints the warnings - it just doesn't act on the -Werror flag for them.

Upvotes: 9

mojuba
mojuba

Reputation: 12227

This disables precisely one type of warnings, the #warning directive, so I presume it's the safest solution to this problem:

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-W#warnings"
#include <evilheader.h>
#pragma GCC diagnostic pop

(Edit: Sorry, turns out gcc is actually clang on my system, so may not work with your genuine gcc)

Upvotes: 2

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