Functions Library – Arma 3

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{{arma3}}'s '''Functions Library''' is the way to declare mission, campaign or addon's [[Function]]s. The main difference from older [[:Category:Functions Library|Function Libraries]] is that it runs automatically and does not require a Functions module.


Arma 3 '''Functions Library''' is pack of routine script functions available from anywhere in game. Main difference from older [[Functions Library]] is that it runs automatically and doesn't require Functions manager to be present.
The advantages of using the Functions Library over e.g [[execVM]] an [[SQF Syntax|SQF]] file are as follow:
 
# '''Automatic compilation upon mission start''' into a global variable - no need to remember direct paths to files.
== Finding a Function ==
# '''Anti-hack protection''' using [[compileFinal]] (see {{Link|Arma 3: Writing a Function#Recompiling}} and [[BIS_fnc_recompile]])
[[File:A3_functionwViewer.png|300px|thumb|right|Functions Viewer]]
# '''Listing in the [[Arma 3: Functions Viewer|Functions Viewer]]'''
Before you can use a function, you first need to find it. The easiest way is to access the '''Functions Viewer''':
# '''Advanced debugging options'''
 
# '''Optional immediate execution upon mission start''', without need for manual call
* In editor, click on [[File:icon editor functions.png|20px]] icon or press Ctrl + F
# '''Potential performance improvements'''
* In mission, access the [[Mission_Editor:_Debug_Console|debug console]] (automatically visible in pause menu of an editor mission) and click on '''FUNCTIONS''' button.
 
Once in the '''Functions Viewer''', you can filter all available functions by location, projects and categories.
 
When you find the desired function, look at the code preview on the right. Every function has a header where you can find basic description of its functionality including required arguments, returned values and sometimes examples of use.
 
{{note|Some functions, especially the older ones, may have missing or incomplete headers.<br />We do our best to update them, but if you find some issues, feel free to report them in the [http://feedback.arma3.com/ Feedback Tracker].}}
 
 
All functions are also listed in [[:Category:Arma_3:_Functions|Arma 3 Functions]] category.
 
== Calling a Function ==
Functions can be launched in mission, intro and outro using this [[call]] or [[spawn]] commands:
_returnedValue = ''arguments'' [[call]] ''functionName'';
''arguments'' [[spawn]] ''functionName'';
 
=== Arguments ===
Arguments are data sent into the function, affecting its behavior.
 
They can be '''mandatory''' or '''optional'''.
* Mandatory arguments are required for function to run. When missing, the function usually stops and throws an error.
* Optional arguments allows more detailed configuration. If you dont send them, the function will use pre-defined default values.
 
{{note|Within the function, '''arguments''' are called '''parameters''', or simply params.}}
 
 
For example, let's take a look at [[BIS_fnc_endMission]], a function which ends a mission with animated closing shot. This is what the header says:
/*
Author: Karel Moricky
Description:
Ends mission with specific ending.
<span style="color:DarkCyan;">Parameter(s):
0 (Optional):
STRING - end name (default: "end1")
ARRAY in format [endName,ID], will be composed to "endName_ID" string
1 (Optional): BOOL - true to end mission, false to fail mission (default: true)
2 (Optional):
BOOL - true for signature closing shot (default: true)
NUMBER - duration of a simple fade out to black</span>
Returns:
BOOL
*/


As you can see, all arguments are marked optional and you can call the function without them.


[] call BIS_fnc_endMission;
{{Feature|important|This page is about {{arma3}} Functions Library.
:This will result in successfull ending of type "end1", preceeded with the signature [[Debriefing|closing shot]].
* For {{arma2}}/{{Name|arma2oa|short}}, see [[Arma 2: Functions Library]].
* For {{tkoh}}, see [[Take On Helicopters: Functions Library]].
}}


["end2"] call BIS_fnc_endMission;
:Set the ending type to "end2", while keeping the other arguments intact.


["end2", false, false] call BIS_fnc_endMission;
== Function Declaration ==
:Fail the mission without any effect, using "end2" type.


Functions are configured within the {{hl|CfgFunctions}} class.


However, what should you do if you want to set the '''only''' last argument without affecting the previous ones? The solution is simple - put an empty variable [[nil]] on their place.
Mission and campaign specific functions can be configured in [[Description.ext]]/[[Campaign Description.ext]], while addon functions are defined in [[Config.cpp]].
Configuration structure is the same in both cases.


<nowiki>[</nowiki>[[nil]], [[nil]], false] call BIS_fnc_endMission;
:Disable the closing effects, but keep the other aguments intact (successful "end1").


{{note|Some older functions are incompatible with this syntax and using nil would break them. See their header for more information.}}
{{Feature|informative|The root directory (noted as '''&lt;ROOT&gt;''' on this page) is the origin from which the game will try to load function files. It depends on {{hl|CfgFunctions}}' location:
* if [[Description.ext]], '''&lt;ROOT&gt;''' means the [[Mission Editor: External#Mission Folder|mission's root]] directory
* if [[Campaign Description.ext]], '''&lt;ROOT&gt;''' means the campaign's root directory
* if in config, '''&lt;ROOT&gt;''' means the '''game'''<nowiki/>'s root directory. The addon path needs to be set manually.
}}


=== Returned Value ===
Functions executed by [[call]] command can return back a value. Let's take a look at [[BIS_fnc_sideName]]:


/*
See a basic example config:
Author: Karel Moricky
  class '''CfgFunctions'''
Description:
Returns side name
Parameter(s):
0: SIDE or NUMBER - either side or side ID
<span style="color:DarkCyan;">Returns:
STRING</span>
*/
The function returns a [[String]] - localized name of a side.
_westName = [[west]] call BIS_fnc_sideName;
:Variable _westName will now be "BLUFOR" (or other name, based on selected language)
 
=== Multiplayer ===
Functions executed using [[call]] or [[spawn]] command will run only on the computer which triggered them. If you'd wish to execute a function remotely on specific clients, use either [[remoteExec]] or [[remoteExecCall]].<br>
[arguments] [[remoteExec]] ["functionName",target,isPersistent];
 
=== User Interface ===
Anywhere outside of running mission, refer to the functions stored in [[uiNamespace]].
  ''arguments'' [[call]] ([[uiNamespace]] [[getVariable]] ''"functionName"'');
 
== Adding a Function ==
When writing a script, consider registering it into the Functions Library.
 
Main benefits:
# '''Automatic compilation upon mission start''' into a global variable - no need to remember direct paths to files.
# '''Anti-hack protection''' using [[compileFinal]] (see [[#Recompiling|Recompiling ]] for more info)
# '''Listing in the Functions Viewer'''
# '''Advanced debugging options'''
# '''Optional immediate execution upon mission start''', without need for manual call
# '''Potential performance improvements'''
 
 
Mission and campaign specific functions can be configured in [[Description.ext]], while addon functions are defined in [[Config.cpp]]. Configuration structure is the same in both cases.
 
=== Tag ===
Functions are configured within CfgFunctions class. To prevent duplicities, every author must create a subclass with unique ''tag'' and place functions inside it. The tag name will be used when composing a function name.
class CfgFunctions
  {
  {
  class <span style="color:green;">myTag</span>
  class {{Color|purple|TAG}}
  {
  {
  class Anything
  class {{Color|darkorange|Category}}
  {
  {
  tag = "<span style="color:green;">myTag</span>"; {{codecomment|//Custom tag name}}
  class {{Color|teal|functionName}} {};
requiredAddons[] = {"A3_Data_F"}; {{codecomment|//Optional requirements of CfgPatches classes. When some addons are missing, functions won't be compiled.}}
  };
  };
  };
  };
  };
  };
* The function's name will be '''{{Color|purple|TAG}}'''_fnc_'''{{Color|teal|functionName}}'''
* The function will be loaded:
** from config: {{hl|'''&lt;ROOT&gt;'''\{{Color|darkorange|Category}}\'''fn_'''{{Color|teal|functionName}}'''.sqf'''}}
** from description.ext: {{hl|'''&lt;ROOT&gt;'''\'''Functions'''\{{Color|darkorange|Category}}\'''fn_'''{{Color|teal|functionName}}'''.sqf'''}}
{{Feature|important|
'''config.cpp only''':
* {{hl|<ROOT>}} in mods is defined by the {{hl|file}} mandatory attribute - see the {{Link|#file}} section below.
* Anywhere outside of running mission, refer to the functions stored in [[uiNamespace]]. e.g: <sqf>arguments call (uiNamespace getVariable "TAG_fnc_functionName");</sqf>
}}
=== Config Levels ===


=== Path ===
A '''CfgFunctions''' config is made of three levels: Tag, Category, and Function.
==== File Path ====
 
The easiest and the most transparent way is to set path for each function.
==== Tag ====
To prevent duplicates, every author must create a subclass with a unique {{Color|purple|[[Scripting Tags|tag]]}} and create functions under it.
The tag name will be used when composing a function name (e.g [[BIS_fnc_spawnGroup|'''BIS'''_fnc_spawnGroup]]).
  class CfgFunctions
  class CfgFunctions
  {
  {
  class <span style="color:green;">myTag</span>
  class {{Color|purple|TAG}}
  {
  {
  class myCategory
  class Category
  {
  {
  class <span style="color:teal;">myFunction</span> {file = "<span style="color:DarkOrange;">myFile.sqf</span>";};
  class myFunction {};
  };
  };
  };
  };
  };
   
This will try to compile function '''<big><span style="color:green;">myTag</span>_fnc_<span style="color:teal;">myFunction</span></big>''' from the following file:
  class TAG_WeaponManagement
''%ROOT%''\<span style="color:DarkOrange;">myFile.sqf</span>
Where ''%ROOT%'' is either '''[[Mission_Editor:_External#Mission_Folder|mission root]]''' (where mission.sqm file is), or the '''game root''' (path to an addon is not included and has to be part of the file path, e.g., <span style="color:DarkOrange;">myAddon\myFile.sqf</span>).
 
==== Folder Path ====
You can set folder path and leave the function paths undefined. The functions will then be loaded from the folder.
class CfgFunctions
{
  class <span style="color:green;">myTag</span>
  {
  {
  class myCategory
'''tag''' = {{Color|purple|"TAG"}}; {{cc|the function will be named '''{{Color|purple|TAG}}_fnc_myOtherFunction'''}}
  class Category
  {
  {
file = "<span style="color:DarkOrange;">myPath</span>";
  class myOtherFunction {};
  class <span style="color:teal;">myFunction</span> {};
  };
  };
  };
  };
  };
  };
Compile function '''<big><span style="color:green;">myTag</span>_fnc_<span style="color:teal;">myFunction</span></big>''' from the following file:
''%ROOT%''\<span style="color:DarkOrange;">myPath</span>\fn_<span style="color:teal;">myFunction</span>.sqf
<span style="color:DarkOrange;">myPath</span> can be a folder or multiple folders, e.g., <span style="color:DarkOrange;">myFolder\mySubfolder</span>


==== Default Path (Mission Only) ====
===== Attributes =====
In a mission, you can leave also the folder path undefined and let functions be loaded from the default directory.
====== tag ======
The {{hl|tag}} attribute can override the config {{Color|green|tag}} set differently.
 
==== Category ====
The category name changes the function's category in the [[Arma 3: Functions Viewer|Functions Viewer]]. It does not change the function's name, only the loading path.
  class CfgFunctions
  class CfgFunctions
  {
  {
  class <span style="color:green;">myTag</span>
  class TAG
  {
  {
  class <span style="color:crimson;">myCategory</span>
  class {{Color|darkorange|Category}}
  {
  {
  class <span style="color:teal;">myFunction</span> {};
  class myFunction {};
};
class OtherCategory
{
'''file''' = "{{Color|darkorange|My}}\{{Color|darkorange|Category}}\{{Color|darkorange|Path}}";
class myFunction {}; {{cc|file path will be '''&lt;ROOT&gt;'''\{{Color|darkorange|My}}\{{Color|darkorange|Category}}\{{Color|darkorange|Path}}\fn_myFunction.sqf";}}
};
class DataCategory
{
'''requiredAddons[]''' = {{Color|darkorange|{ "A3_Data_F" }<nowiki/>}}; {{cc|Optional requirements of [[CfgPatches]] classes. If some addons are missing, category functions will not be compiled.}}
class myDataFunction {};
  };
  };
  };
  };
  };
  };
Compile function '''<big><span style="color:green;">myTag</span>_fnc_<span style="color:teal;">myFunction</span></big>''' from the following file:
''%ROOT%''\functions\<span style="color:crimson;">myCategory</span>\fn_<span style="color:teal;">myFunction</span>.sqf


=== Attributes ===
===== Attributes =====
Apart from already mentioned ''file'', function class can have additional attributes:
====== file ======
The {{hl|file}} attribute can override the category's loading path segment - it is required for mods.
 
====== requiredAddons ======
The category can skip loading if a required addon is missing by setting its dependency with the {{hl|requiredAddons}} attribute.
 
==== Function ====
{{Feature|informative|By convention, the function class should be named in '''camelCase''' and not have its first letter capitalised (e.g PascalCase):
* {{Icon|checked}} TAG_fnc_{{Color|teal|myFunction}}
* {{Icon|unchecked}} TAG_fnc_{{Color|teal|MyFunction}}
* {{Icon|checked}} TAG_fnc_{{Color|teal|POWRescue}}
}}
  class CfgFunctions
  class CfgFunctions
  {
  {
  class <span style="color:green;">myTag</span>
  class TAG
  {
  {
  class myCategory
  class Category1
{
class {{Color|teal|myFunction}} {};
};
class Category2
  {
  {
  class <span style="color:teal;">myFunction</span>
  file = "Path\To\Category";
class myFunction
  {
  {
  preInit = 1; {{codecomment|//(formerly known as "forced") 1 to call the function upon mission start, <u>before</u> objects are initialized. Passed arguments are ["preInit"]}}
  '''file''' = "{{Color|teal|My}}\{{Color|teal|Function}}\{{Color|teal|Filepath.sqf}}"; {{cc|file path will be '''&lt;ROOT&gt;'''\{{Color|teal|My}}\{{Color|teal|Function}}\{{Color|teal|Filepath.sqf}}", ignoring "Path\To\Category"}}
postInit = 1; {{codecomment|//1 to call the function upon mission start, <u>after</u> objects are initialized. Passed arguments are ["postInit", didJIP]}}
};
preStart = 1; {{codecomment|//1 to call the function upon game start, before title screen, but after all addons are loaded (config.cpp only)}}
ext = ".fsm"; {{codecomment|//Set file type, can be ".sqf" or ".fsm" (meaning scripted FSM). Default is ".sqf".}}
class {{Color|teal|myFSMFunction}}
headerType = -1; {{codecomment|//Set function header type: -1 - no header; 0 - default header; 1 - system header.}}
{
  recompile = 1; {{codecomment|//1 to recompile the function upon mission start (config.cpp only; functions in description.ext are compiled upon mission start already)}}
'''preInit''' = 1;
'''postInit''' = 1;
'''ext''' = ".fsm";
  '''preStart''' = 1;
'''recompile''' = 1;
  };
  };
  };
  };
  };
  };
  };
  };
All of these attributes are case sensitive.<br />


==== Pre and Post Init ====
===== Attributes =====
''preInit'' and ''postInit'' attributes are truly powerful ones, as they let you execute your function at the beginning of '''every''' mission. Use them with caution!.<br />
{| class="wikitable sortable"
''preInit'' are '''called''' [[Scheduler#Unscheduled_Environment|unscheduled]] so suspension is not allowed. Parameters passed are [ "preInit" ].<br />
! rowspan="2" | Attribute
''postInit'' are '''called''' [[Scheduler#Scheduled_Environment|scheduled]] so suspension is allowed but any long term suspension will halt the mission loading until suspension has finished. Parameters passed are [ "postInit", [[didJIP]] ].<br />
! rowspan="2" | Description
! colspan="2" | Available in
|- style="font-size: 0.9em"
! [[Description.ext]]
! [[config.cpp]]
|-
| file
| the {{hl|file}} attribute can be used to manually set the file path.
{{Feature|important|The '''file''' entry '''overrides''' Category's set path and ignores it entirely (they are not merged).}}
| style="text-align: center" | {{Icon|checked}}
| style="text-align: center" | {{Icon|checked}}
|-
| preInit
| the {{hl|preInit}} attribute (formerly known as "forced") can be set to 1 to call the function upon mission start, before objects are initialized.<br>Passed arguments are <sqf inline>["preInit"]</sqf>.
The function is run in an '''[[Scheduler#Unscheduled Environment|unscheduled environment]]'''.
| style="text-align: center" | {{Icon|checked}}
| style="text-align: center" | {{Icon|checked}}
|-
| postInit
| the {{hl|postInit}} attribute can be set to 1 to call the function upon mission start, after objects are initialized.<br>Passed arguments are <sqf inline>["postInit", didJIP]</sqf>.
The function is run in a '''[[Scheduler#Scheduled Environment|scheduled environment]]''' so suspension is allowed, but '''any long term suspension will halt the mission loading until suspension is done'''.
| style="text-align: center" | {{Icon|checked}}
| style="text-align: center" | {{Icon|checked}}
|-
| ext
| the {{hl|ext}} attribute can be used to set function file's type; it can be one of:
* ".sqf" (default)
* ".fsm" (see [[FSM]])
| style="text-align: center" | {{Icon|checked}}
| style="text-align: center" | {{Icon|checked}}
|-
| preStart
| the {{hl|preStart}} attribute can be set to 1 to call the function upon game start, before title screen, but after all addons are loaded.
| style="text-align: center" | {{Icon|unchecked}}
| style="text-align: center" | {{Icon|checked}}
|-
| recompile
| the {{hl|recompile}} attribute can be set to 1 to recompile the function upon mission start (functions in [[Description.ext]] are always compiled upon mission (re)start)
| style="text-align: center" | {{Icon|unchecked}}
| style="text-align: center" | {{Icon|checked}}
|-
| headerType
| the {{hl|headerType}} adds code to the beginning of functions that can:
* Set up the [[#Meta Variables|Meta Variables]] _fnc_scriptParent and _fnc_scriptName
* Name the current scope via the command [[scriptName]]
* Adds debug information by saving the current execution order in the [[Array]] _fnc_scriptMap.<br/>
Possible values are:
* -1: No header - Adds nothing, literally adds a blank [[String]] to the beginning of functions. The functions will have no debug or {{Link|#Meta Variables}} assigned for it and the scope will not be named. Useful to reduce the performance overhead or if custom debug system is used.
* 0: Default header - The default header changes based on the current [[#Debug Modes|Debug Mode]]
* 1: System header - Incorporates the [[#Meta Variables|Meta Variables]] _fnc_scriptParent. Also names the current scope.<sqf>
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then { '%1' } else { _fnc_scriptName };
scriptName '%1';
</sqf>
See the following section for more information.
| style="text-align: center" | {{Icon|checked}}
| style="text-align: center" | {{Icon|checked}}
|}


{{Feature|important|Notes about {{hl|preInit}} and {{hl|postInit}} defined in '''config.cpp''':
* these attributes will make the function run '''on each, every and any mission start'''
* Any scripting error will prevent the mission from being loaded correctly
* Any scripting error will prevent the mission from being loaded correctly
* Server admins might blacklist your addon if they find out you're using the function for hacking.
* Server admins might blacklist the whole addon if they find out the function is used for hacking
<!-- HIDDEN as per note in talk page by STR
}}


==== Header Types ====
The different header types add code to the begining of your functions that can..
*Set up the [[#Meta Variables|Meta Variables]] _fnc_scriptParent and _fnc_scriptName
*Name the current scope via the command [[scriptName]]
*Adds debug information by saving the current execution order in the [[Array]] _fnc_scriptMap.


== Advanced Knowledge ==


:'''''No Header'''''<br />
=== Meta Variables ===
:Adds nothing, literally adds a blank [[String]] to the begining of your function. The function will have no debug or [[#Meta Variables|Meta Variables]] assigned for it and the scope will not be named.
 
 
:'''''System Header'''''<br />
:Incorporates the [[#Meta Variables|Meta Variables]] _fnc_scriptParent. Also names the current scope.
:{|
|
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then {'%1'} else {_fnc_scriptName};
scriptName '%1';
|}
 
 
:'''''Default Header'''''<br />
:The default header changes based on the current [[#Debug Mode:Debug Mode]]
 
::''Debug Mode 0'' - default<br />
::Incorporates the [[#Meta Variables|Meta Variables]] _fnc_scriptParent and _fnc_scriptName and names the current scope.
::{|
|
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then {'%1'} else {_fnc_scriptName};
private _fnc_scriptName = '%1';
scriptName _fnc_scriptName;
|}
 
::''Debug Mode 1''<br />
::As per ''Debug Mode 0'' and also saves the current execution order in the [[Array]] _fnc_scriptMap.
::{|
|
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then {'%1'} else {_fnc_scriptName};
private _fnc_scriptName = '%1';
scriptName _fnc_scriptName;
private _fnc_scriptMap = if (isNil '_fnc_scriptMap') then {[_fnc_scriptName]} else {_fnc_scriptMap + [_fnc_scriptName]};
|}
 
::''Debug Mode 2''<br />
::As per ''Debug Mode 1'' and also outputs execution order using [[textLogFormat]] ( textLogFormat is not available in the retail version of Arma3 ) is it available in Diagnostics exe?
::{|
|
private _fnc_scriptNameParent = if (isNil '_fnc_scriptName') then {'%1'} else {_fnc_scriptName};
private _fnc_scriptName = '%1';
scriptName _fnc_scriptName;
private _fnc_scriptMap = if (isNil '_fnc_scriptMap') then {[_fnc_scriptName]} else {_fnc_scriptMap + [_fnc_scriptName]};
textLogFormat ['%1 : %2', _fnc_scriptMap joinString ' >> ', _this];
|}
END HIDDEN -->
 
=== Initialization Order ===
''See [[Initialization_Order]]''
 
== Writing a Function ==
The most important thing to remember when writing a function is that other people than you are going to use it. Most of them won't understand how does it work, expecting it to do its job without problems.
 
Your function must be '''robust'''. It shouldn't allow passing arguments of incorrect [[Data Types]] in. When some values are incorrect, it should throw an error explaining what went wrong and how to fix it. And above all, its header must provide complete explanation of usage.
{{Important|What is not documented, does not exist!}}
 
=== Loading Parameters ===
Arguments are the only way how to interact with your function. Let's now see how to make sure they are loaded properly.
 
We have this very simple function which will let a unit watch a position:
[[params]] ["_unit", "_target"];
_unit [[doWatch]] _target;
 
Expected way how to call the function is by correctly defining all arguments:
{|
| [[File:Ico_ok.png]]
|
[player, position myCar] call myTag_fnc_myFunction;
|}
 
However, the function will break down when you try to send only one argument in:
{|
| [[File:Ico_none.png]]
|
[player] call myTag_fnc_myFunction;
|}
 
Furthermore, using wrong data type will also lead to a problem:
{|
| [[File:Ico_none.png]]
|
[player, 0] call myTag_fnc_myFunction;
|}
 
Variabe ''_target'' expects position array in format [x,y,z]. Scripting error will appear when different number of elements is used:
{|
| [[File:Ico_none.png]]
|
[player, [1, 2, 3, 4]] call myTag_fnc_myFunction;
|}


* '''_fnc_scriptName''': [[String]] - Name of the script
* '''_fnc_scriptNameParent''': [[String]] - Name of the parent script
* '''_fnc_scriptMap''': [[Array]] - List of all parent scripts


As you can see there, the most common problems are:
=== Debug Modes ===
# '''Param of wrong data type is sent'''
# '''Param is missing'''
# '''Param is an array expecting specific number of elements, but different number is sent'''


Rather than check for these exceptions yourself, you can use existing [[param]] command which will do it for you:
Developers can access several debug modes using ''[[BIS_fnc_functionsDebug]]'' function. '''For this to work [[Description.ext#allowFunctionsRecompile|function recompiling]] has to be allowed!'''
_unit = param [<span style="color:darkorange;">0</span>, <span style="color:teal;">objNull</span>, <span style="color:crimson;">[objNull]</span>];
For multiple parameters, use the [[params]] command instead.
params [[<span style="color:green;">"_unit"</span>, <span style="color:teal;">objNull</span>, <span style="color:crimson;">[objNull]</span>], [<span style="color:green;">"_target"</span>, <span style="color:teal;">[0, 0, 0]</span>, <span style="color:crimson;">[[], objNull]</span>, <span style="color:indigo;">[2, 3]</span>]];
_unit doWatch _target;
* In a [[params]] array first argument is the name of the  <span style="color:green;">'''private variable'''</span>. In [[param]] it's the <span style="color:darkorange;">'''index'''</span> number.
* Second argument is the <span style="color:teal;">'''default value'''</span>. It will be used when the argument is missing, is [[nil]] or when wrong data type is used.
* Next is optional <span style="color:crimson;">'''array of compatible data types'''</span>. They are defined by an example of the type, e.g. [[objNull]] will mean an object is allowed. When wrong data type is sent into your function, BIS_fnc_param will log an error message explaining what went wrong and use the default value.
* The last, also optional argument is an <span style="color:indigo;">'''array of required array sizes'''</span>. [2,3] means only array with 2 or 3 elements are allowed. When incorrectly large array is sent into your function, BIS_fnc_param will log an error message explaining what went wrong and use the default value.


==== Debug Mode 0 ====
default - incorporates the [[#Meta Variables|Meta Variables]] _fnc_scriptParent and _fnc_scriptName and names the current scope.
<sqf>
private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName };
private _fnc_scriptName = "%1";
scriptName _fnc_scriptName;
</sqf>


Let's see what will happen when you try to use the wrong examples now:
==== Debug Mode 1 ====
{|
As per ''Debug Mode 0'' and also saves the current execution order in the [[Array]] _fnc_scriptMap.
| [[File:Ico_ok.png]]
<sqf>
|
private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName };
[player] call myTag_fnc_myFunction;
private _fnc_scriptName = "%1";
|}
scriptName _fnc_scriptName;
: ''_target'' is undefined. Default <span style="color:teal;">[0,  0, 0]</span> is used instead. No error message is logged.
private _fnc_scriptMap = if (isNil "_fnc_scriptMap") then { [_fnc_scriptName] } else { _fnc_scriptMap + [_fnc_scriptName] };
</sqf>


{|
==== Debug Mode 2 ====
| [[File:Ico_ok.png]]
As per ''Debug Mode 1'' and also outputs execution order using [[textLogFormat]] ( textLogFormat is not available in the retail version of Arma3 ) is it available in Diagnostics exe?
|
<sqf>
[nil, position myCar] call myTag_fnc_myFunction;
private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName };
|}
private _fnc_scriptName = "%1";
: ''_unit'' is undefined (nil is passed instead). Default <span style="color:teal;">objNull</span> is used instead. No error message is logged.
scriptName _fnc_scriptName;
private _fnc_scriptMap = if (isNil "_fnc_scriptMap") then { [_fnc_scriptName] } else { _fnc_scriptMap + [_fnc_scriptName] };
textLogFormat ["%1 : %2", _fnc_scriptMap joinString " >> ", _this];
</sqf>


{|
| [[File:Ico_warning.png]]
|
[player, 0] call myTag_fnc_myFunction;
|}
: ''_target'' has wrong <span style="color:crimson;">type</span>. Default <span style="color:teal;">[0, 0, 0]</span> is used instead. Error message is logged.


{|
== See Also ==
| [[File:Ico_warning.png]]
|
[player, [1, 2, 3, 4]] call myTag_fnc_myFunction;
|}
: ''_target'' has wrong <span style="color:indigo;">size</span>. Default <span style="color:teal;">[0, 0, 0]</span> is used instead. Error message is logged.


* [[Initialisation Order]]
* [[Arma 3: Functions Viewer]]
* [[:Category:Arma 3: Functions|Arma 3 Functions]]
* [[Arma 3: Writing a Function|Writing a Function Tutorial]]


Additionally, when only one argument is used, you can send it into the function directly without need to have it in an array.
{|
| [[File:Ico_ok.png]]
|
player call myTag_fnc_myFunction;
|}
=== Returning Value ===
Users will often save result of your function to a variable. If no value is returned, the variable would be [[nil]] and could lead to script errors.
_myVar = [player, position myCar] call myTag_fnc_myFunction;
It's good practice to '''always''' return a value, even if it would be simple [[true]] marking the function as completed. Let's use the example function from above:
params [["_unit", objNull, [objNull]], ["_target", [0, 0, 0], [[], objNull], [2, 3]]];
_unit doWatch _target;
'''true'''
=== Showing Errors ===
While [[param]] and [[params]] can filter out the most common issues, sometimes your function will have special rules which will need to be handled. Let's return back to our example function, where we'd want to terminate the function with error when ''_unit'' is dead:
params [["_unit", objNull, [objNull]], ["_target", [0, 0, 0], [[], objNull], [2, 3]]];
'''if (!alive _unit) exitwith {["Unit %1 must be alive.", _unit] call [[BIS_fnc_error]]; false};'''
_unit doWatch _target;
true
Notice that we're returning [[false]] at the end of [[exitWith]] code.
{{Important|Error states must always return value of the same type as when everything is fine ([[Boolean]] in this case).}}
BIS_fnc_error accepts [[String]] and [[Array]] of [[format]]ted ext. The error is logged into [[RPT]] and if the mission is previewd from the editor, it will also appear on screen.
{|
| [[RPT]]
|
"User1/log: ERROR: [BIS_fnc_respawnTickets] #0: 0 is type SCALAR, must be NAMESPACE, SIDE, GROUP, OBJECT, BOOL. true used instead."
|-
| In-game
| [[File:A3 functions error.jpg|800px|On-screen error]]
|}
=== Logging ===
Apart from errors, you can print any debug message you need. Use one of the following functions:
* [[BIS_fnc_log]] - log a data of any type (e.g., [[String]], [[Number]], [[Object]], ...)
* [[BIS_fnc_logFormat]] - log [[format]]ted text
Profile name and function name will automatically appear in the output text, helping you identify the source.
Usage examples:
{| class="wikitable"
! Expression
! [[RPT]] Output
|-
|
<span style="color:green;">"Hello World"</span> call BIS_fnc_log;
|
"User1/BIS_fnc_log: [myTag_fnc_myFunction] <span style="color:green;">Hello World</span>"
|-
|
<span style="color:green;">42</span> call BIS_fnc_log;
|
"User1/BIS_fnc_log: [myTag_fnc_myFunction] <span style="color:green;">42</span>"
|-
|
[<span style="color:green;">"I'm playing %1"</span>, [[missionName]]] call BIS_fnc_logFormat;
|
"User1/BIS_fnc_log: [myTag_fnc_myFunction] <span style="color:green;">I'm playing FalconWing</span>"
|}
To prevent RPT spam, logging is by default enabled only when previewing a mission from the editor. To force it in the mission everywhere, use the following [[Description.ext]] attribute:
allowFunctionsLog = 1;
=== Recompiling ===
Once compiled, functions remain unchanged and editing their file won't have any effect in the game. To adjust functions on the fly, you can manually trigger their recompilation.
1 call [[BIS_fnc_recompile]];
:Recompiles all functions. Can be also achieved by clicking on RECOMPILE button in the Functions Viewer
"''functionName''" call [[BIS_fnc_recompile]];
:Recompile the given function
As a security measure, functions are by default protected against rewriting during the mission. <u>This restriction does not apply in missions previewed from the editor and in missions with the following attribute in [[Description.ext]]</u>:
allowFunctionsRecompile = 1;
"Recompile" button in the functions viewer will be enabled only when recompiling is allowed.
=== Meta Variables ===
System is adding header with basic meta data to all functions. Following local variables are declared there:
* '''_fnc_scriptName''': [[String]] - Function name (e.g., myTag_fnc_myFunction)
* '''_fnc_scriptNameParent''': [[String]] - Name of q function from which the current one was called (_fnc_scriptName used when not defined)
<!--* '''_fnc_scriptMap''': ARRAY - List of all parent scripts (available only in debug mode 1 and higher, see [[#Debug_Mode|above]]).-->
{{Important|Do not modify these values!}}


<!--
{{GameCategory|arma3|Editing}}
=== Debug Mode ===
[[Category: Functions Library]]
Developers can access several debug modes using ''[[BIS_fnc_functionsDebug]]'' function.
# '''No debug'''
#* Default
# '''Save script map'''
#* Variable ''_fnc_scriptMap'' tracking script execution progress is stored in function header
# '''Save and log script map'''
#* Variable ''_fnc_scriptMap'' tracking script execution progress is stored in functions header and it's printed to debug log.
{{Important|Function recompiling has to be allowed!}}
-->

Latest revision as of 12:01, 2 October 2024

Arma 3's Functions Library is the way to declare mission, campaign or addon's Functions. The main difference from older Function Libraries is that it runs automatically and does not require a Functions module.

The advantages of using the Functions Library over e.g execVM an SQF file are as follow:

  1. Automatic compilation upon mission start into a global variable - no need to remember direct paths to files.
  2. Anti-hack protection using compileFinal (see Arma 3: Writing a Function - Recompiling and BIS_fnc_recompile)
  3. Listing in the Functions Viewer
  4. Advanced debugging options
  5. Optional immediate execution upon mission start, without need for manual call
  6. Potential performance improvements


⚠
This page is about Arma 3 Functions Library.


Function Declaration

Functions are configured within the CfgFunctions class.

Mission and campaign specific functions can be configured in Description.ext/Campaign Description.ext, while addon functions are defined in Config.cpp. Configuration structure is the same in both cases.


ⓘ
The root directory (noted as <ROOT> on this page) is the origin from which the game will try to load function files. It depends on CfgFunctions' location:


See a basic example config: 

class CfgFunctions
{
	class TAG
	{
		class Category
		{
			class functionName {};
		};
	};
};
  • The function's name will be TAG_fnc_functionName
  • The function will be loaded:
    • from config: <ROOT>\Category\fn_functionName.sqf
    • from description.ext: <ROOT>\Functions\Category\fn_functionName.sqf
⚠
config.cpp only:
  • <ROOT> in mods is defined by the file mandatory attribute - see the file section below.
  • Anywhere outside of running mission, refer to the functions stored in uiNamespace. e.g:
    arguments call (uiNamespace getVariable "TAG_fnc_functionName");

Config Levels

A CfgFunctions config is made of three levels: Tag, Category, and Function.

Tag

To prevent duplicates, every author must create a subclass with a unique tag and create functions under it. The tag name will be used when composing a function name (e.g BIS_fnc_spawnGroup). 

class CfgFunctions
{
	class TAG
	{
		class Category
		{
			class myFunction {};
		};
	};

	class TAG_WeaponManagement
	{
		tag = "TAG"; // the function will be named TAG_fnc_myOtherFunction
		class Category
		{
			class myOtherFunction {};
		};
	};
};
Attributes
tag

The tag attribute can override the config tag set differently.

Category

The category name changes the function's category in the Functions Viewer. It does not change the function's name, only the loading path. 

class CfgFunctions
{
	class TAG
	{
		class Category
		{
			class myFunction {};
		};

		class OtherCategory
		{
			file = "My\Category\Path";
			class myFunction {}; // file path will be <ROOT>\My\Category\Path\fn_myFunction.sqf";
		};

		class DataCategory
		{
			requiredAddons[] = { "A3_Data_F" }; // Optional requirements of CfgPatches classes. If some addons are missing, category functions will not be compiled.
			class myDataFunction {};
		};
	};
};
Attributes
file

The file attribute can override the category's loading path segment - it is required for mods.

requiredAddons

The category can skip loading if a required addon is missing by setting its dependency with the requiredAddons attribute.

Function

ⓘ
By convention, the function class should be named in camelCase and not have its first letter capitalised (e.g PascalCase):
  • Checked TAG_fnc_myFunction
  • Unchecked TAG_fnc_MyFunction
  • Checked TAG_fnc_POWRescue
class CfgFunctions
{
	class TAG
	{
		class Category1
		{
			class myFunction {};
		};

		class Category2
		{
			file = "Path\To\Category";
			class myFunction
			{
				file = "My\Function\Filepath.sqf"; // file path will be <ROOT>\My\Function\Filepath.sqf", ignoring "Path\To\Category"
			};

			class myFSMFunction
			{
				preInit		= 1;
				postInit	= 1;
				ext			= ".fsm";
				preStart	= 1;
				recompile	= 1;
			};
		};
	};
};
Attributes
Attribute Description Available in
Description.ext config.cpp
file the file attribute can be used to manually set the file path.
⚠
The file entry overrides Category's set path and ignores it entirely (they are not merged).
 Checked Checked
preInit the preInit attribute (formerly known as "forced") can be set to 1 to call the function upon mission start, before objects are initialized.
Passed arguments are ["preInit"].

The function is run in an unscheduled environment.

Checked Checked
postInit the postInit attribute can be set to 1 to call the function upon mission start, after objects are initialized.
Passed arguments are ["postInit", didJIP].

The function is run in a scheduled environment so suspension is allowed, but any long term suspension will halt the mission loading until suspension is done.

Checked Checked
ext the ext attribute can be used to set function file's type; it can be one of:
  • ".sqf" (default)
  • ".fsm" (see FSM)
 Checked Checked
preStart the preStart attribute can be set to 1 to call the function upon game start, before title screen, but after all addons are loaded. Unchecked Checked
recompile the recompile attribute can be set to 1 to recompile the function upon mission start (functions in Description.ext are always compiled upon mission (re)start) Unchecked Checked
headerType the headerType adds code to the beginning of functions that can:
  • Set up the Meta Variables _fnc_scriptParent and _fnc_scriptName
  • Name the current scope via the command scriptName
  • Adds debug information by saving the current execution order in the Array _fnc_scriptMap.

Possible values are:

See the following section for more information.

Checked Checked
⚠
Notes about preInit and postInit defined in config.cpp:
  • these attributes will make the function run on each, every and any mission start
  • Any scripting error will prevent the mission from being loaded correctly
  • Server admins might blacklist the whole addon if they find out the function is used for hacking


Advanced Knowledge

Meta Variables

  • _fnc_scriptName: String - Name of the script
  • _fnc_scriptNameParent: String - Name of the parent script
  • _fnc_scriptMap: Array - List of all parent scripts

Debug Modes

Developers can access several debug modes using BIS_fnc_functionsDebug function. For this to work function recompiling has to be allowed!

Debug Mode 0

default - incorporates the Meta Variables _fnc_scriptParent and _fnc_scriptName and names the current scope.

private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName }; private _fnc_scriptName = "%1"; scriptName _fnc_scriptName;

Debug Mode 1

As per Debug Mode 0 and also saves the current execution order in the Array _fnc_scriptMap.

private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName }; private _fnc_scriptName = "%1"; scriptName _fnc_scriptName; private _fnc_scriptMap = if (isNil "_fnc_scriptMap") then { [_fnc_scriptName] } else { _fnc_scriptMap + [_fnc_scriptName] };

Debug Mode 2

As per Debug Mode 1 and also outputs execution order using textLogFormat ( textLogFormat is not available in the retail version of Arma3 ) is it available in Diagnostics exe?

private _fnc_scriptNameParent = if (isNil "_fnc_scriptName") then { "%1" } else { _fnc_scriptName }; private _fnc_scriptName = "%1"; scriptName _fnc_scriptName; private _fnc_scriptMap = if (isNil "_fnc_scriptMap") then { [_fnc_scriptName] } else { _fnc_scriptMap + [_fnc_scriptName] }; textLogFormat ["%1 : %2", _fnc_scriptMap joinString " >> ", _this];


See Also

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