main

Can the arguments of main’s signature in C++ have the unsigned and const qualifiers? [duplicate]

The C++98 standard says in section 3.6.1 paragraph 2 An implementation shall not predefine the main function. This function shall not be overloaded. It shall have a return type of type int, but otherwise its type is implementation-defined. All implementations shall allow both the following definitions of main: int main() and int main(int argc, char* … Read more

No Main() in WPF?

The Main() method is created automatically. If you want to provide your own you have to (tested in VS2013, VS2017 and VS2019): Right-click App.xaml in the solution explorer, select Properties Change ‘Build Action’ to ‘Page’ (initial value is ‘ApplicationDefinition’) Then just add a Main() method to App.xaml.cs. It could be like this: [STAThread] public static … Read more

Difference between int main() and int main(void)?

In C++, there is no difference. In C, the difference is questionable. Some love to argue that the latter version (the one without void) is technically just a common implementation extension and not guaranteed to work by the standard because of the wording in the standard. However, the standard clearly states that in a function … Read more

WINMAIN and main() in C++ (Extended)

About the functions. The C and C++ standards require any program (for a “hosted” C or C++ implementation) to have a function called main, which serves as the program’s startup function. The main function is called after zero-initialization of non-local static variables, and possibly but not necessarily (!, C++11 §3.6.2/4) this call happens after dynamic … Read more

Is char *envp[] as a third argument to main() portable

The function getenv is the only one specified by the C standard. The function putenv, and the extern environ are POSIX-specific. EDIT The main parameter envp is not specified by POSIX but is widely supported. An alternative method of accessing the environment list is to declare a third argument to the main() function: int main(int … Read more

What is “main” in Ruby?

Everything in Ruby occurs in the context of some object. The object at the top level is called “main”. It’s basically an instance of Object with the special property that any methods defined there are added as instance methods of Object (so they’re available everywhere). So we can make a script consisting entirely of: puts … Read more