Using undocumented functions is risky for production software, as they may change without notice between Windows versions.
To find documentation for MessageBox , search for "MessageBoxA winuser" or navigate to the Win32 API reference. user32.dll documentation
Have a tip for undocumented user32.dll behavior? Share it in the comments below. user32.dll documentation
If you have ever developed a Windows application—whether in C, C++, C#, Python, or even Rust—you have almost certainly interacted with user32.dll without even realizing it. This dynamic link library is one of the most critical components of the Windows operating system. It sits just above the kernel (NTOSKRNL.exe) and serves as the primary API for managing user interface elements. user32.dll documentation