WoW:API UnitGUID: Difference between revisions

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(replaced "Speculation" section, general cleanup)
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The top three digits are reserved. It's unknown if any of the lower digits are also reserved.
The top three digits are reserved. It's unknown if any of the lower digits are also reserved.


Renaming and transfering to another server, or to another account gives your character a new GUID. Slouken confirms[http://forums.worldofwarcraft.com/thread.html?topicId=2968233433&postId=44201363100&sid=1#231] that player GUIDs are unique even in crossserver battlegrounds, which strongly indicates that the GUIDs are stored globally, either per region or per datacenter.
Renaming and transfering to another server, or to another account gives your character a new GUID. Player GUIDs remain unique in cross-realm battlegroups [http://forums.worldofwarcraft.com/thread.html?topicId=2968233433&postId=44201363100&sid=1#231].
 
Slouken, in the link earlier, also states that "Players keep their GUID forever, ..." My empirical studies has shown that this is not true, certain actions like transfering and renaming your character will give you a new GUID. Restoring a character from backup is untested wether it restores the old GUID or not.




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* The last six digits are the spawn counter.
* The last six digits are the spawn counter.


You must log out before the pet gets this GUID, if querried during the same session that you tamed it, your pet will have its pre-taming GUID.
You must log out before the pet gets this GUID. If queried during the same session that you tamed it, your pet will have its pre-taming GUID.


== Spawn counter ==
== Spawn counter ==
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  0xF53 & 0x00F = 0x003
  0xF53 & 0x00F = 0x003


This GUID is for a normal NPC, not a pet and not a player.ts.
This GUID is for a normal NPC, not a pet and not a player.


We can also extract the Unit ID by taking the sixth to tenth digit and converting it to decimal form: "4D2B", or converted to decimal form "19755". A quick visit to wowhead shows that the NPC with that id is "Mo'arg Weaponsmith", [http://www.wowhead.com/?npc=19755]. All "Mo'arg Weaponsmiths" will have that id to identify them.
We can also extract the Unit ID by taking the sixth to tenth digit and converting it to decimal form: "4D2B", or converted to decimal form "19755". A quick visit to wowhead shows that the NPC with that id is "Mo'arg Weaponsmith", [http://www.wowhead.com/?npc=19755]. All "Mo'arg Weaponsmiths" will have that id to identify them.
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The last six digits, "008852" is the spawn counter. There will never be two "Mo'arg Weaponsmith", possible even never two mobs in the outside world, with the same spawn number. This spawn counter, combined with the rest makes it possible to always refer to exactly this "Mo'arg Weaponsmith", and not the one next to it.
The last six digits, "008852" is the spawn counter. There will never be two "Mo'arg Weaponsmith", possible even never two mobs in the outside world, with the same spawn number. This spawn counter, combined with the rest makes it possible to always refer to exactly this "Mo'arg Weaponsmith", and not the one next to it.


== Speculations ==
== Cross-server and GUID "uniqueness" ==
Player GUIDs are local on a per-server basis, making the "global" scope to be bound to the specific server. Every time a character is created, a new GUID is assigned from a simple +1 counter and then given to that character. It should be noted that the act of transferring characters, either server to server, account to account, or even account to account while remaining on the same server will generate a new character GUID, because of how the process works (the character "ceases to exist" for a short period, and is then recreated). This act erases friend and ignore lists. Renaming a character does not trigger a new GUID, as that process is much simpler than a full character move.
 
Uniqueness is guaranteed in cross-realm battlegrounds by masking the player GUID with a server specific unique identifier, when needed.


The values returned from players indicate how recently those players were created. Someone with the number 1000 would be the 1000th created character across all servers in the same battlegroup, similar to how NPC GUIDs increment as they spawn. This is evident when comparing old characters with newly created ones, and allows for globally unique player GUIDs in battlegrounds. In addition, creating two new characters in quick succession on same-battlegroup servers will yield GUIDs very near to each other in the predicted order. Each NPC that respawns adds a number higher, so 4294967295 means that there have been 4294967294 NPCs before that one spawned. Renaming does not change the player UnitGUID value so you can track players trough renames using this; unfortunately if you transfer your character, it obtains a new GUID as if it were a new character. In instances, spawned NPC/mobs return the same value, unlike outside of instances. Player pets keep their values when despawned and then respawned, so pets appear to have their own GUID counter like characters do.
NPC GUID collisions have also been observed. It is unknown why or when in specific they occur, but differing mob types have had a NPC ID number which corresponded to an entirely different NPC. This is considered a very rare phenomenon.  


== Returns ==
== Returns ==

Revision as of 20:25, 28 May 2009

← WoW API < UnitGUID

Returns the GUID of the unit specified. Works on both players and NPC. 

UnitGUID("unit")

What does it all mean?

The GUID is a unique hexadecimal string for each unit in the game. Just how unique are they? Slouken[1] has this to say on it: 

A monster has a single GUID from spawn until death (or despawn). When it respawns it gets a new GUID.
Pets get a new GUID each time they are summoned.
Monster and pet GUIDs can be recycled after server (or instance) restart.
Players keep their GUID forever, and are unique even in cross-server battlegrounds.

The strings always begin with '0x', which is the normal prefix for hexadecimal numbers. The '0x' prefix isn't actually part of the ID number, it's just to say "this is a hex string."


Determine if it's a player, pet or NPC

  • It's a player if the upper bits masked with 0x00f = 0x000
  • It's a creature if the upper bits masked with 0x00f = 0x003
  • It's a pet if the upper bits masked with 0x00f = 0x004
  • It's a vehicle (carries others) if the upper bits masked with 0x00f = 0x005

Since, as explained below, attempting to convert a GUID to a number in Lua results in garbage, it may be easier to use substrings than actually converting to a number and masking, as in this example: 

 myGUID = "0xF530004D2B008852" -- the example used below
 myUnitType = myGUID:sub(5,5)

The value you get will be either 0, 3, 4, or 5 corresponding to players, creatures, pets and vehicles respectively.

Format for players

  • The GUID is a simple number in the order characters are created. An older character has a lower number than a new.

The top three digits are reserved. It's unknown if any of the lower digits are also reserved.

Renaming and transfering to another server, or to another account gives your character a new GUID. Player GUIDs remain unique in cross-realm battlegroups [2].


Format for non-pet NPCs

  • The first three characters masked with 0x00f will result in 0x003.
  • The next three digits are unknown. It's usually '000'.
  • The next four digits are the NPC id.
  • The last six digits are the spawn counter.

If you take the 'NPC id' and convert it to decimal you can check wowhead and see what NPC it is. See examples below.


Format for pets

  • The first three characters masked with 0x00f will result in 0x004.
  • The next seven digits are the pet id (a counter like players based on the order of creation).
  • The last six digits are the spawn counter.

You must log out before the pet gets this GUID. If queried during the same session that you tamed it, your pet will have its pre-taming GUID.

Spawn counter

Spawn counter is a unique number given all non-player mobs. It's a simple incremental number, instances and outside world are probably handled differently. The number in itself is not relevant, but combined with the rest of the string it always give this exact mob a unique identifier.


An example of a GUID

We have a GUID: "0xF530004D2B008852".

First of all, let's find out what kind of unit it is. Take the first three digits in the GUID, ie "F53" (or 0xF53 to show it's an hex value) and apply an AND mask of 0x00F. 

0xF53 & 0x00F = 0x003

This GUID is for a normal NPC, not a pet and not a player.

We can also extract the Unit ID by taking the sixth to tenth digit and converting it to decimal form: "4D2B", or converted to decimal form "19755". A quick visit to wowhead shows that the NPC with that id is "Mo'arg Weaponsmith", [3]. All "Mo'arg Weaponsmiths" will have that id to identify them.

The last six digits, "008852" is the spawn counter. There will never be two "Mo'arg Weaponsmith", possible even never two mobs in the outside world, with the same spawn number. This spawn counter, combined with the rest makes it possible to always refer to exactly this "Mo'arg Weaponsmith", and not the one next to it.

Cross-server and GUID "uniqueness"

Player GUIDs are local on a per-server basis, making the "global" scope to be bound to the specific server. Every time a character is created, a new GUID is assigned from a simple +1 counter and then given to that character. It should be noted that the act of transferring characters, either server to server, account to account, or even account to account while remaining on the same server will generate a new character GUID, because of how the process works (the character "ceases to exist" for a short period, and is then recreated). This act erases friend and ignore lists. Renaming a character does not trigger a new GUID, as that process is much simpler than a full character move.

Uniqueness is guaranteed in cross-realm battlegrounds by masking the player GUID with a server specific unique identifier, when needed.

NPC GUID collisions have also been observed. It is unknown why or when in specific they occur, but differing mob types have had a NPC ID number which corresponded to an entirely different NPC. This is considered a very rare phenomenon.

Returns

GUID
Returns the unit GUID in hexdecimal.


Example

local name = UnitName("target"); local guid = UnitGUID("target"); ChatFrame1:AddMessage(name.." has the GUID: "..guid);

Result 

Cyan has the GUID: 0x00000000012729FD

Conversion to decimal?

GUIDs are 64-bit numbers, and are far too long to convert to decimal numbers using lua's libraries as a whole. E.g. running tonumber(guid, 16) will produce erronous results.

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