export_url_vars argsWhat it does:
Returns a string of key=value pairs suitable for inclusion in a URL; you can pass it any number of variables as arguments. If any are defined in the caller's environment, they are included. See also export_entire_form_as_url_varsDefined in: /web/philip/packages/acs-core/utilities-procs.tcl
Source code:
set params {} foreach var $args { upvar 1 $var value if { [info exists value] } { lappend params "$var=[ns_urlencode $value]" } } return [join $params "&"]