Code blocks command line arguments
- #Code blocks command line arguments how to#
- #Code blocks command line arguments code#
- #Code blocks command line arguments windows#
This extension is also common in other compilers for Windows and UNIX systems. The main or wmain signatures allow an optional Microsoft-specific extension for access to environment variables.
#Code blocks command line arguments code#
To return an exit code when main or wmain is declared as void, you must use the exit function. If you declare main or wmain as returning void, you can't return an exit code to the parent process or the operating system by using a return statement. It's available for symmetry when main doesn't return a value. This extension is also available in some other compilers, but its use isn't recommended. Returning void from mainĪs a Microsoft extension, the main and wmain functions can be declared as returning void (no return value). For more information, see Using generic-text mappings. The _tmain macro and other macros that begin with _t are useful for code that must build separate versions for both narrow and wide character sets. _tmain resolves to main unless _UNICODE is defined. You can also use the Microsoft-specific _tmain, which is a preprocessor macro defined in tchar.h. Here's the effective declaration syntax for wmain: int wmain() If you design your source code to use Unicode wide characters, you can use the Microsoft-specific wmain entry point, which is the wide-character version of main. The following sections describe Microsoft-specific behavior. You can use GetModuleFileName to retrieve the executable name, and its fully-qualified path. If you use both the first and second arguments ( lpApplicationName and lpCommandLine), argv may not be the executable name. However, on Windows it's possible to spawn a process by using CreateProcess.
#Code blocks command line arguments how to#
The last argument from the command line is argv, and argv is always NULL.įor information on how to suppress command-line processing, see Customize C++ command-line processing.īy convention, argv is the filename of the program. By convention, argv is the command with which the program is invoked. The argc parameter is always greater than or equal to 1.Īn array of null-terminated strings representing command-line arguments entered by the user of the program. The names argc and argv are traditional, but you can name them whatever you like.Īn integer that contains the count of arguments that follow in argv.
The types for argc and argv are defined by the language. The arguments for main allow convenient command-line parsing of arguments. If no return value is specified in main, the compiler supplies a return value of zero.
If it did, the declaration syntax for main would look like this: int main() The main function doesn't have a declaration, because it's built into the language. Can't be overloaded (see Function overloading).Several restrictions apply to the main function that don't apply to any other C++ functions. In Microsoft C++, global static objects are also initialized before entry to main. (Dynamic-link libraries and static libraries don't have a main function.) The main function is where your source code begins execution, but before a program enters the main function, all static class members without explicit initializers are set to zero. If you try to compile a C++ program without a main function, the compiler raises an error. All C++ programs must have a main function.