Custom C startup code (mainCRTStartup) implementation for GCC/MinGW.

Nocrt0 is a custom C startup code without any dependencies of the standard C runtime libraries. It is intended for building very small executable files under OS Windows(R). Nocrt0 was successfully tested with GCC/MinGW and Pelles C. It is also possible that nocrt0 could be adapted for other C compilers, including Microsoft Visual C, as well, however, the source code requires some of C99 language features, so it cannot be compiled with msvc directly.

There are two modules: nocrt0w for GUI applications, and nocrt0c for console applications. Simply add the correct source into your project and build it without linking to the default C startup code (hint: for GCC you will need -nostartfiles or -nostdlib option).

The process of building nocrt0 can also be controlled with the following DEFINEs:

-D_UNICODE
-DNODEFAULTLIBS
-DARGV={own | msvcrt | shell32 | none}

-D_UNICODE builds "wide" version of the startup code (wmain or wWinMain).

-DNODEFAULTLIBS when defined compiles built-in implementation of _alloca() and __chkstk(). You might need it if you don't want to link with libgcc.a.

-DARGV is used for a console application (nocrt0c) only. It selects the type of the underlying implementation of the standard command-line parser (argc/argv). own (default) is the built-in implementation (note: envp is not supported and is always set to NULL); msvcrt makes use of an external function __getmainargs() (which is normally imported from msvcrt.dll); shell32 relies on CommandLineToArgvW() function from shell32.dll; none is for applications that do not need any command-line processing (int main(void)).