How do I get the error level of commands in a pipe in Windows batch programming?

Question

Batch files return the error code of the last command by default.

Is it somehow possible to return the error code of a former command. Most notably, is it possible t

Answer 1

After about one day of digging, I found a way to do that:

set error_=0
9>&1 1>&2 2>&9 (for /f "delims=" %%i in ('9^>^&1 1^>^&2 2^>^&9 ^(^(^(2^>^&1 call "%homeDir%%1"^) ^|^| ^(1^>^&2 2^>nul echo FAILED^)^) ^| 2^>nul "%homeDir%mtee" /T /+ "%homeDir%logs\%date_%_%1.log"^)') do (set error_=1))

exit /b %error_%

In the example above "%homeDir%%1" is being executed and its output is piped to "%homeDir%mtee". This line detects failures (I'd suggest you to draw a diagram of batch contexts and their stdin/stdout/stderr assignments in order to understand what it does :-) ). I did not find a good way to extract the actual errorlevel. The best thing I got was to replace the 'echo' command with some batch script call 'call rc.bat' which look like:

@echo %errorlevel%

and then replace 'set error_=1' with 'set error_=%%i'.

But the problem is that this call may fail too, and it is not easy to detect that. Still, it is much better than nothing -- I did not find any solution for that on the Internet.