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(void)
should not be used to ignore return values, use 'std::ignore =
' instead (es.48)
Remarks
Excerpt from the C++ Core Guideline ES.48:
Never cast to
(void)
to ignore a[[nodiscard]]
return value. If you deliberately want to discard such a result, first think hard about whether that is really a good idea (there is usually a good reason the author of the function or of the return type used[[nodiscard]]
in the first place). If you still think it's appropriate and your code reviewer agrees, usestd::ignore =
to turn off the warning which is simple, portable, and easy to grep.
Code analysis name: USE_STD_IGNORE_INSTEAD_OF_VOID_CAST
Example
Use std::ignore
instead of cast to void
:
struct S{};
[[nodiscard]] S getS();
void function() {
(void) getS(); // C26457
std::ignore = getS(); // OK
}