How do you make the warning come up that has the words 'suspicious' and '-Wmain' in it? - c++

Question

It's a simple question really, and refers to Linux (as opposed to Windows or Mac).
How do you generate a warning message from the C or C++ compiler that must have the word 'suspicious' in it, and must refer to (-Wmain).
(update)
Thanks Boann - I got some of those Warnings, but I also got Error - error: ‘::main’ must return ‘int’.
The reason I'm asking this question is that a week ago my compiler (GCC 4.8.1) came out with this warning saying 'suspicious' and that it was caused by Wmain. So I put -Wno-main and the warning went away and it compiled fine. Just recently it has started complaining making it an actual Error and not compiling. So I'm kind of worried that somehow the mother ship has covertly updated my compiler over the internet, without me knowing, and changed it to treat it as error. (I was probably using 'int4' as the return type which I forever have typedef'd as signed long int.
I note there's -Wmain referenced in g++ man page so it must be for something, but what warning is there that isn't overruled by an error??
At offset 557284 (decimal) of the g++ executable I found "Warn about suspicious declarations of "main".

Answer 1

For what it's worth,
struct suspicious {};
int main(suspicious) {}
Output with g++ -Wall, GCC 4.8.2:
warning: first argument of 'int main(suspicious)' should be 'int' [-Wmain]

Answer 2

If you refer to the -Wmain parameter of GCC, you get the warning by giving main odd arguments, an odd return type, or giving it static linkage. This will do it:
static float main(float x) {
return 0;
}
Compiled with gcc -Wmain, it displays these warnings; they do not actually contain the word 'suspicious' though:
warning: return type of 'main' is not 'int'
warning: first argument of 'main' should be 'int'
warning: 'main' takes only zero or two arguments
warning: 'main' is normally a non-static function

Answer 3

I just downloaded the sources for gcc 4.8.1 and searched all relevant files for the word "suspicious".
There are a number of occurrences, but as far as I can tell, there's no way an error message for a C or C++ source file can contain the word "suspicious". It's possible but unlikely that there was a local modification.
Is it possible that you're mistaken about what the error message said? If you have a log containing the error message, please update your question to show the exact message your received.
If you're concerned that your compiler may have been updated without your knowledge, you might check the timestamp of the compiler executable and of any programs it invokes (use gcc -v to check that). But gcc itself doesn't automatically update itself. If you're using it on a system administered by someone else, automatic updates are to be expected. If you administer the system yourself, you may have configured it to update software without manual intervention; if so, that's not a gcc issue. I don't know what "mother ship" you're referring to.