Exit Codes Windows -
PowerShell-native commands return rich objects, not exit codes. When you run an external .exe , PowerShell captures its exit code in $LASTEXITCODE , but the PowerShell process's own exit code is set only by exit $n . A script that runs non-existent.exe will see $LASTEXITCODE = 0xC0000135 (STATUS_DLL_NOT_FOUND), but the PowerShell process itself exits with 0 unless you explicitly forward it. 4. The Debugger's Compass: Interpreting Exit Codes as Clues For a systems engineer, an unexpected exit code is a compressed diagnostic. Here’s how to decompress it:
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." exit codes windows
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. The code 3 means nothing about your logic—it
In the seemingly sterile output of a command-line program—a lone integer returned to the operating system—lies a sophisticated, often misunderstood contract between a process and its caller. On Windows, this integer is the exit code (or "return code"), and while the convention 0 for success and non-zero for failure is universal, the depth beneath is uniquely shaped by Windows' architecture, its legacy subsystems, and the perils of cross-platform assumptions. 1. The Kernel's Handshake: How Exit Codes Really Work When a Windows process terminates—whether by returning from main() , calling ExitProcess() , or suffering an unhandled exception—the kernel records a 32-bit unsigned integer inside the EPROCESS block. This value persists until the process object is reaped by WaitForSingleObject() or GetExitCodeProcess() . The CRT wraps main()
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 yes, it's either an NTSTATUS (0xCxxxxxxx) or HRESULT (0x8xxxxxxx). Use the Visual Studio tool err.exe or net helpmsg :
