What happens if main() does not return an int value?

Question

I know that in C compilers the main() function is called by the _start() function which has code something like this:

exit(main());         


        

Answer 1

In C++ it would be a compile error to return anything other than int from main():

error: ‘::main’ must return ‘int’

In C it is a warning, you will get a float reinterpreted as an int: for example, 2.1F would be reinterpreted as 224.