[[Property:title|Definition file]]
[[Property:weight|2]]
[[Property:uuid|3a4b017c-ede1-7af1-2934-c7a28b303764]]
The syntax is pretty simple when you understand what you need to export a feature: you need the name of the '''feature''', the name of the concerned '''class''', and the name of a '''creation procedure'''. What is optional is to specify an '''alias''', an '''index''' and a '''calling convention'''. The index and calling convention are mainly used to create a DLL for windows, and the alias to export the feature under a different name. 

===Syntax===

{| border="1"
|- 
|  '''Export_feature''' 
| Class_name [Creation_part] ":" Feature [Optional_part]
|- 
|  '''Creation_part''' 
| "(" feature_name ")"
|- 
|  '''Optional_part''' 
| [Index_part] [Alias_part]
|- 
|  '''Index_part''' 
| "@" integer
|- 
|  '''Alias_part''' 
| "Alias" alias_name
|- 
|  '''Call_type_part''' 
| "call_type" call_type_name
|}


===Example===

<code lang=text>
ROOT_CLASS (make): foo @ 4 Alias my_foo call_type __stdcall</code>

===Constraints===
* on the class: <div>The class cannot be deferred or generic.</div>
* on the feature: <div>It could be any feature except an attribute, an external feature or a deferred feature.</div>
* on the creation procedure: <div>It must have zero argument, and no return type.</div>
* on the alias name: <div>It must be a valid name for a C function.</div>
* on the index: <div>It must be strictly positive.</div>
* on the call type: <div>It must be a valid call type for the targeted platform (useful for Windows only). For Visual C++, the valid calling conventions are __stdcall, __cdecl and __fastcall.</div>

For each feature the required fields are the '''class''', the '''creation procedure''', and of course the '''feature''' itself. 
* If the feature is a creation procedure then do not specify any creation, it will use the feature as creation. For example '''ROOT_CLASS: make'''. 
* If the class has no creation procedure, do not specify any creation. default_create will be automatically used.

===A definition file===

<code lang=text>
-- EXPORTED FEATURE(s) OF THE SHARED LIBRARY
-- SYSTEM : demo

-- CLASS [BAR]
-- Here get_string uses make_b as creation
BAR (make_b) : get_string
-- Here print_bar uses make_a as creation
BAR (make_a) : print_bar

-- CLASS [ROOT_CLASS]
-- Here the feature is also a creation
ROOT_CLASS : make
ROOT_CLASS (make) : foo
ROOT_CLASS (make) : test_bar</code>