declaring dynamic globals

Dear List, I am trying to create a function that will clean up the file name and copy an uploaded file to its final destination. The one I have relies on declaring the globals $uploadFile , $uploadFile_name and $uploadFile_size. However, my current application calls for 3 upload fields that have unique names. I have tried to pass the field name as an argument in the function call. Then use that value to declare the globals like so: function UploadImage($Field) { global ${$Field}; global ${$Field . "_name}; global ${$Field . "_size}; } But I get a parse error "expecting string" on the first global declaration. Is there a way to do what I want to do? Kathleen