If I make a batch script named temp.bat (for example) containing:
exit /b 1
When I run it in various ways, I get different behavior on my 32-bit XP system vs. a 64-bit XP system.
On 32-bit:
> temp.bat
> echo %ERRORLEVEL%
1
> cmd /c temp.bat
> echo %ERRORLEVEL%
0
On 64-bit:
> temp.bat
> echo %ERRORLEVEL%
1
> cmd /c temp.bat
> echo %ERRORLEVEL%
1
I've searched through the cmd.exe options and I have been unable to find any options controlling how it propagates errorlevel information from batch scripts. At this point I'm unable to find any rational explanation for this difference.
You have to be careful with exit /b since it does not actually work correctly in all instances. For example:
temp.bat&&echo 0||echo 1
If temp.bat contains exit /b 1 you would expect 1 to be printed, but it is not. Sadly, the only way to really set a working exit code for a batch file is to use @%COMSPEC% /C exit 1 as the last line in the batch file
The problem with Anders's example is that it uses a .bat file. If you use a .cmd file, exit works as documented.
The main point of having both .bat and .cmd files seems to be backward compatibility: if it's executing a .bat file, cmd tries to emulate the pre-NT CLI, command.com, which had much simpler error handling.
At least that's my surmise. I stumbled on this thread while googling for official docs on the .bat/.cmd thing, which I can't seem to find.
