Calling function from included batch file with a parameter

Question

In my main batch file I include another batch file and want to call a function defined in there, code looks like following:

@echo off
call define_wait.bat

i         


        

Answer 1

I wasn't aware of this until jeb commented it, but here's a quick demonstration of the call bug he mentioned, using some utility functions I had lying around.

functions.bat:

:length <"string">
rem // sets errorlevel to the string length (not including quotation marks)
setlocal disabledelayedexpansion
if "%~1"=="" (endlocal & exit /b 0) else set ret=1
set "tmpstr=%~1"
for %%I in (4096 2048 1024 512 256 128 64 32 16 8 4 2 1) do (
    setlocal enabledelayedexpansion
    if not "!tmpstr:~%%I,1!"=="" (
        for %%x in ("!tmpstr:~%%I!") do endlocal & (
            set /a ret += %%I
            set "tmpstr=%%~x"
        )
    ) else endlocal
)
endlocal & exit /b %ret%

:password 
rem // prompts user for password, masks input, and sets return_var to entered value
setlocal disabledelayedexpansion

main.bat:

@echo off & setlocal

rem // demo return value
call :password pass

setlocal enabledelayedexpansion
echo You entered !pass!

rem // demo bubbling up of %ERRORLEVEL%
call :length "!pass!"
echo Password length is %ERRORLEVEL%

endlocal
goto :EOF

rem // ====== FUNCTION DECLARATIONS =======

:length <"string">
:password 
functions.bat %*

Output:

Password? *********
You entered something
Password length is 9

This web page offers an explanation:

If you execute a second batch file without using CALL you may run into some buggy behaviour: if both batch files contain a label with the same name and you have previously used CALL to jump to that label in the first script, you will find execution of the second script starts at the same label. Even if the second label does not exist this will still raise an error "cannot find the batch label". This bug can be avoided by always using CALL.

If you've ever done any coding in C++, it helps to think of the labels in main.bat as function declarations in a .h file, while the labels in functions.bat would correspond to function definitions in a .cpp file. Or in .NET, the main.bat labels would be like DllImport("functions.bat") so to speak.