Codes Windows — Exit

If your main() throws an uncaught C++ exception, the CRT catches it, calls terminate() , and then ExitProcess(3) . The code 3 means nothing about your logic—it simply signals "CRT abnormal termination."

This layering leads to a key insight: . The default for a thread is STATUS_THREAD_TERMINATED (0x00000100); for a process, it is STATUS_PENDING (0x00000103) until termination, then the final code. 2. The Semantic Wasteland: What Does Non-Zero Mean? Unlike Unix, where exit codes are small (0–255) and often mapped to sysexits.h conventions, Windows exit codes are full 32-bit values, blending several distinct categories: exit codes windows

Crucially, the exit code is the return value of main() in the C runtime sense. The CRT wraps main() , captures its return value, and passes it to ExitProcess() . If you never call ExitProcess explicitly, the CRT does it for you. If your main() throws an uncaught C++ exception,

These are STILL_ACTIVE (thread) and STATUS_PENDING (process). Seeing them from GetExitCodeProcess means you called it before the process actually exited. This is a classic race. The CRT wraps main() , captures its return

In cmd.exe , the exit code of a batch file is the exit code of the last command executed . A batch file that copies a file and then echoes a message will return 0 even if the copy failed, because echo always succeeds. This forces developers to use exit /b %errorlevel% explicitly.

> net helpmsg 2 The system cannot find the file specified. If the program is well-known (e.g., robocopy , xcopy ), consult its documentation—they reuse Win32 error codes with different meanings.