Functions

Functions AKA subprograms can be emulated using CALL, labels, SETLOCAL and ENDLOCAL.

An example of a function that determines arithmetic power:

@echo off
call :power 2 4
echo %result%
rem Prints 16, determined as 2 * 2 * 2 * 2
goto :eof

rem __Function power______________________
rem Arguments: %1 and %2
:power
setlocal
set counter=%2
set interim_product=%1
:power_loop
if %counter% gtr 1 (
  set /a interim_product=interim_product * %1
  set /a counter=counter - 1
  goto :power_loop
)
endlocal & set result=%interim_product%
goto :eof

While the goto :eof at the end of the function is not really needed, it has to be there in the general case in which there is more than one function.

The variable into which the result should be stored can be specified on the calling line as follows:

@echo off
call :sayhello result=world
echo %result%
exit /b

:sayhello
set %1=Hello %2
REM Set %1 to set the returning value
exit /b

In the example above, exit /b is used instead of goto :eof to the same effect.

Also, remember that the equal sign is a way to separate parameters. Thus, the following items achieve the same:

• call :sayhello result=world
• call :sayhello result world
• call :sayhello result,world
• call :sayhello result;world

(See command-line arguments as a reminder)

Links:

• Functions at ss64