basic_start.md

• A hosted implementation shall contain a global function called main in one of the specified forms [basic.start.main]

  • 6.8.3.1
  • Example:

  void main() {}

  • Rationale:

  • Tools

    • Compiler static analysis, generates warnings or errors for void main

• The function main shall not be used within a program [basic.start.main]

  • 6.8.3.1

  • Examples:

    • Is it illegal to take address of main() function?
    • Why does gcc warn about decltype(main()) but not clang?

    printf( “%p\n”, &main ) ;
    decltype(main()) x = 0;

    int main() {
      std::cout << reinterpret_cast<void*>(&main) ;
    }

  • Tools

    • Compiler static analysis via -pedantic flag gcc/clang for taking address of main
    • Compiler static analysis via -pedantic flag gcc/clang decltype main

  • Rationale:

    • From ARM section 3.4 Start and Termination

      This is to ensure full freedom of the implementation of the interface between a C++ program and its environment. One could imagine an implementation where main() was not implemented as a function.

    • [ub] What does "The function main shall not be used within a program" mean?