UUIDs (Universally Unique Identifier) or GUIDs (Globally Unique Identifier) are defined in this document: [L1 ]
PT 8-Jul-2004: I have just added a UUID module to tcllib that implements type 4 uuids from the draft specification document. eg:
% package require uuid
1.0.0
% set id [uuid::uuid generate]
140d7c2c-4502-4144-6ae0-a4692e8ed819
% if {[uuid::uuid compare $id $id] == 0} { puts "ids equal" }Windows provides an API for generating GUIDs and some extensions make use of this, but I needed a pure-Tcl UUID generator. So, I came up with this. This proc, by no means, conforms to the standards discussed in the above document, but it does produce unique identifiers that are good enough for me. :) Damon Courtney
proc uuid {} {
## Try and get a string unique to this host.
set str [info hostname]$::tcl_platform(machine)$::tcl_platform(os)
binary scan $str h* hex
set uuid [format %2.2x [clock seconds]]
append uuid -[string range [format %2.2x [clock clicks]] 0 3]
append uuid -[string range [format %2.2x [clock clicks]] 2 5]
append uuid -[string range [format %2.2x [clock clicks]] 4 end]
append uuid -[string range $hex 0 11]
return $uuid
}
proc guid {} {
## Return a GUID for Windows, which is just an uppercase UUID with brackets.
return \{[string toupper [uuid]]\}
}I wrote a Windows C based Tcl extension for this too a few months back. The C source is really short and simple. It simply calls some underlying Windows APIs. Here's a link to the source code: