CodeQL library for C/C++
codeql/cpp-all 0.13.1 (changelog, source)

Member predicate Function::isMultiplyDefined

Holds if this function is defined in several files. This is illegal in C (though possible in some C++ compilers), and likely indicates that several functions that are not linked together have been compiled. An example would be a project with many ‘main’ functions.

predicate isMultiplyDefined()