CodeQL library for C/C++
codeql/cpp-all 1.1.0 (changelog, source)

Member predicate Options::okToIgnoreReturnValue

Holds if it is reasonable to ignore the return value of function call fc.

By default holds for calls to select where the first argument is 0 (commonly used as a way of sleeping), and any call inside a macro expansion.

predicate okToIgnoreReturnValue(FunctionCall fc)