You can pass a string to a called routine and have it return an environment variable whose name is the string.

Example:

If you wish to determine how many parameters your batch file was passed, and return the results in a environment variable named answer, include the following statement in your batch:

call cntargs answer %*

NOTE: The variable answer need not be defined.

The cntargs batch file could contain:

@echo off
if {%1}
{} @echo Syntax: call cntargs string [arg1 arg2 ... argn]&goto :EOF
setlocal
set /a numargs=0
:numloop
if {%2}
{} endlocal&set /a %1=%numargs%&goto :EOF
set /a numargs=%numargs% + 1
shift /2
goto numloop

After the call cntargs answer %* statement, you can use the answer environment variable, as in @echo My batch was passed %answer% parameters.