FM to read a file path based on AL11 profile

Hi Experts,

Please could you give me a  Function Module name to read directory path via AL11.

Right now i have hard coded as Z:\usr\sap\XXX\TSTBMGS00\data\Files in my code, when I move this code to QA and prod which doesn't work because the file path is hard coded.

I am looking a function module whcih accepts a command as "DIR_INSTANCE"  in put parameter and give out put parameter as Z:\usr\sap\XXX\TSTBMGS00 , then I will concatenate rest of the file name (/data/files/) which is constant across the landscape.

I have gone through forums and found some of the examples but none of them are working as expected.

Thanks

Krishna