How Can I Selectively Disable GCC Warnings within a Specific Code Block?

Disabling GCC Warnings Selectively within a Translation Unit

This question aims to achieve selective disabling of GCC warnings within specific parts of a compilation unit. The desired outcome resembles a preprocessor construct supported by MSVC, as follows:

#pragma warning( push )
#pragma warning( disable : 4723 )
// Code where warning C4723 should be suppressed
#pragma warning( pop )

GCC Diagnostic Pragma

GCC offers a solution through its diagnostic pragma, #pragma GCC diagnostic. However, it operates somewhat differently from the MSVC approach. The syntax is:

#pragma GCC diagnostic [warning|error|ignored] "-W[whatever]"

This pragma can either suppress or ignore specific warnings or errors within the scope of a specific code block.

To disable a particular warning, such as the example C4723, use the following syntax:

#pragma GCC diagnostic warning "-W4723"

Note that the pragma will remain in effect until the end of the code block or until it is terminated by another pragma with the option #pragma GCC diagnostic warning "-W4723" on.

Caveats and Considerations

It's important to consider the following limitations and caveats when using the GCC diagnostic pragma:

• It suppresses warnings for the entire translation unit where it is placed, not just a part of it.
• It cannot be nested, meaning you cannot use another pragma within the scope of an active pragma.
• It can disrupt normal warning behavior, so it's essential to use it judiciously and temporarily to suppress specific warnings.

To achieve the desired behavior—suppressing warnings only for a specific part of a translation unit—it is recommended to selectively include the code that generates the undesired warning in a separate compilation unit and disable warnings for that unit.

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