问题
I have a post-build event that runs some commands for a c# project. The last command would sometimes cause the ERRORLEVEL value not equals to zero and then the build fails.
I want to append an extra line of command to always set the ERRORLEVEL value to zero. What is the most convenient way to do that?
回答1:
if you use exit /b 0 you can return an errorlevel 0 from within a child batch script without also exiting the parent.
回答2:
Seems to do the trick:
ver > nul
Not everything works, and it is not clear why. For example, the following do not:
echo. > nul
cls > nul
回答3:
In a pre- or post-build event, if the return code of an executable is greater than zero, and the call to the executable is not the last line of the pre- or post-build event, a quick way mute it and avoid triggering a check for a non-zero errorlevel is to follow the failing line with a line that explicitly returns zero:
cmd /c "exit /b 0"
This is essentially a generic combination of the previously-mentioned solutions that will work with more than just the last line of a pre- or post-build event.
回答4:
I found that "exit 0" looks like a good way to deal with this problem.
Usage Example:
NET STOP UnderDevService /Y
exit 0
if the UnderDevService service is not started.
回答5:
I personally use this:
cd .
Works even in unix shell.
But, this one might be a bit faster:
type nul>nul
Because Process Monitor shows QueryDirectory calls on cd .
PS:
cd . has another nice side effect in the unix shell. It does restore recreated working directory in the terminal if it has been opened before the erase.
回答6:
I use VERIFY or VERIFY > nul
回答7:
If this is a snippet like "Post-build Event" etc., then you'll be fine appending:
(...) || ver > nul
at the end of the last command.
Alternatively
cmd /c "exit /b 0"
is very clean and non-idiomatic -- a reader who knows Windows shell will know what's going on, and what was your intent.
However, if you're in a batch script, you may want to use subrotines, which are a lightweight equivalent of the "child batch script" from akf's answer.
Have a subroutine:
:reset_error
exit /b 0
and then just
call :reset_error
wherever you need it.
Here's a complete example:
@echo off
rem *** main ***
call :raise_error
echo After :raise_error ERRORLEVEL = %ERRORLEVEL%
call :empty
echo After :empty ERRORLEVEL = %ERRORLEVEL%
call :reset_error
echo After :reset_error ERRORLEVEL = %ERRORLEVEL%
:: this is needed at the end of the main body of the script
goto:eof
rem *** subroutines ***
:empty
goto:eof
:raise_error
exit /b 1
:reset_error
exit /b 0
Which outputs:
After :raise_error ERRORLEVEL = 1
After :empty ERRORLEVEL = 1
After :reset_error ERRORLEVEL = 0
As you see - just calling and returning via goto:eof is not enough.
回答8:
Add >nul after each command that's likely to fail - this seems to prevent the build from failing.
You can still check the result of the command by examining %errorlevel%.
For example:
findstr "foo" c:\temp.txt>nul & if %errorlevel% EQU 0 (echo found it) else (echo didn't find it)
回答9:
Here are some other ways to reset the ErrorLevel state, which even work in MS-DOS (at least for version 6.22):
more < nul > nul
rem // The `> nul` part can be omitted in Windows but is needed in MS-DOS to avoid a line-break to be returned:
sort < nul > nul
The following methods work in MS-DOS only:
command /? > nul
fc nul nul > nul
For the sake of completeness, this sets the ErrorLevel state to 1, valid for both Windows and MS-DOS:
< nul find ""
回答10:
I'm using this:
ping localhost -n 1 >null
回答11:
I always just used;
set ERRORLEVEL=0
I've been using it for donkey's years.
来源：https://stackoverflow.com/questions/1113727/what-is-the-easiest-way-to-reset-errorlevel-to-zero