Lets have the following file called library.cmd :
@echo off
echo -/-/- Batch Functions Library -/-/-
:function1
echo argument1 - %1
goto :eof
To execute only the :function1 without the code of the rest of the file you should put a label :function1 in the caller bat and use it like this:
@echo off
call :function1 ###
exit /b %errorlevel%
:function1
library.bat %*
the output will be (the code outside the function in library.cmd
is not executed):
argument1 - ###
For more info check this.