How to interprete variable in batch string?

Question

i have a problem in a string with variable included
I read a key in registry like this :

call:ReadReg "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders" "Desktop"
echo %RegValue%

:ReadReg
FOR /F "usebackq tokens=1-3" %%A IN (`REG QUERY "%~1" /v "%~2" 2^>nul`) DO (
    set RegName=%%A
    set RegType=%%B
    set RegValue=%%C
)
goto:eof

but the value returned in RegValue is: %USERPROFILE%\Desktop instead of : C:\Documents and Settings\username\Desktop

the ECHO line display :

C:\Documents and Settings\alopez>echo %USERPROFILE%\Bureau
%USERPROFILE%\Bureau

I would like convert the registry value into a good path

Answer 1

Replace set RegValue=%%C with call set RegValue=%%C This will cause variable expansion twice; once for the call command and then again for the set command. Run this example .bat script to see it in action.

@echo off

set x=%%Path%%
echo %x%
echo.
call echo %x%
call set x=%x%
echo.
echo %x%
pause >nul