How Can I Selectively Disable GCC Warnings in Specific Code Sections?

Disabling GCC Warnings for Specific Sections of a Translation Unit

Achieving a similar functionality to the provided MSVC preprocessor code in GCC may not be straightforward, but there is a viable workaround using GCC diagnostic pragmas.

The GCC diagnostic pragma #pragma GCC diagnostic can be employed to manipulate warning and error settings within a translation unit. It allows you to temporarily disable or ignore specific warnings.

To conditionally disable a warning, use the following syntax:

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wwhatever"
// Code that would normally generate the warning
#pragma GCC diagnostic pop

This approach will suppress the specified warning within the defined code block while allowing the warning to be generated elsewhere in the translation unit.

Example:

Imagine a header file math.h that contains a function divide() that may potentially divide by zero. You want to prevent this warning from being issued when including math.h in other source files.

In math.h:

#include <cmath>
int divide(int a, int b) { return std::floor(static_cast<double>(a) / b); }

In a separate source file:

#include "math.h"
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdiv-by-zero"
divide(1, 0); // The warning is suppressed here
#pragma GCC diagnostic pop
divide(2, 3); // Warning is still generated for this call

By selectively disabling warnings in this manner, you can prevent specific parts of your codebase from generating unwanted warnings while still maintaining the desired warning behavior elsewhere.

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