GNU g ++编译器下main（）的返回类型

Question

As per ISO_14882_2014

3.6 Start and termination [basic.start]

3.6.1 Main function [basic.start.main]

2 An implementation shall not predefine the main function. This function shall not be overloaded. It shall have a declared return type of type int, but otherwise its type is implementation-defined.

but otherwise its type is implementation-defined. That means compiler may have its own return type for main() . Can you point me to the location where GNU G++ compiler says about main() 's return type.

Answer 1

The return type must be int ; the "its type" that follows refers to main , not to the return type. That is, the arguments that main takes are implementation defined. Each implementation must, however, provide at least int main() and int main(int, char**) .

Answer 2

Assuming i386 architecture. From glibc start.S we call __libc_start_main . From glibc csu/libc-start.c __libc_start_main we call main with the pointer type int (*main) (int, char **, char **) (the MAIN_AUXVEC_DECL shouldn't be defined on i386 I think, only for powerpc). So the implementation defined type of main function is int main(int, char **, char **) . Because of how stack works on i386, the forms int main(void) and int main() and int main(int) and int main(int, char**) will work. The main return type is int .