Windows Batch noop instruction

[andry81]

There is exist a builtin instruction without ERRORLEVEL change and without arguments. It can be used to concatenate command lines using & operator inside (...) blocks.

Tests:

https://github.com/andry81/contools--debug/tree/HEAD/test_for_concat.bat
https://github.com/andry81/contools/tree/HEAD/scripts/tests/bench/bat/test__call/

@echo off

setlocal

rem `break` as `noop`

call;

break

echo 1.ERRORLEVEL=%ERRORLEVEL%

(call)

break

echo 2.ERRORLEVEL=%ERRORLEVEL%

call;

(
  for %%i in (:) do for %%i in (:) do break ^
  & for %%i in (:) do for %%i in (:) do break ^
  & for %%i in (:) do for %%i in (:) do break
)

echo 3.ERRORLEVEL=%ERRORLEVEL%

Result:

1.ERRORLEVEL=0
2.ERRORLEVEL=1
3.ERRORLEVEL=0

Note

The break in the cmd.exe command line still can change the exit code: #46

Note

The break does change the exit code on SIGINT: #48

[andry81]

Additional feature is that the break is much CTRL+C interruptible, unlike other built in commands like call;.

Tests:

https://github.com/andry81/contools--debug/tree/HEAD/test_skip_terminate_batch_job_by_filter_exit_code_2.bat

@echo off

setlocal

call;

rem requires to press CTRL+C because of infinite for loop
cmd.exe /c @for /L %%i in () do @break || call cmd.exe /c @if %%ERRORLEVEL%% EQU -1073741510 (exit 9009) else exit %%ERRORLEVEL%%

echo ERRORLEVEL=%ERRORLEVEL%

If replace @break by @call;, then the CTRL+C press reaction will be much unresponsive.