Merge pull request maul-esel#17 from Uberi/gh-pages

Add section to DllCall post

en/_posts/2011-11-24-DllCalls.markdown

@@ -1,5 +1,5 @@
 ---
-title: Working with Windows API
+title: Working with external functionality
 layout: post
 permalink: /en/DllCalls.html
 ---
@@ -105,3 +105,25 @@ IDCANCEL := 2 ; define the constant as pointed out on msdn
 if (result == IDCANCEL)
 	MsgBox You canceled.
 {% endhighlight %}
+
+### Exported data
+Rarely, DLLs may export variables in addition to functions; for example, the Raydium Game Engine DLL. Although it is not possible to retrieve or store values to this variable directly using DllCall(), it is possible to use the [GetProcAddress()](http://msdn.microsoft.com/en-us/library/windows/desktop/ms683212.aspx) WinAPI function to do so:
+{% highlight ahk linenos %}; any AutoHotkey version
+
+;compatibility types
+UPtr := A_PtrSize ? "UPtr" : "UInt"
+AStr := A_IsUnicode ? "AStr" : "Str"
+
+;load the library that contains the exported variable
+hModule := DllCall("LoadLibrary","Str","Raydium.dll",UPtr)
+
+;obtain the address of the variable "raydium_joy_x"
+pJoystickX := DllCall("GetProcAddress",UPtr,hModule,AStr,"raydium_joy_x",UPtr)
+
+;retrieve a float value from the address
+JoyStickX := NumGet(pJoystickX + 0,0,"Float")
+MsgBox, The joystick position in the x-axis is currently %JoystickX%.
+
+;store a float value in the memory location pointed to by the address
+NumPut(0.8,pJoystickX + 0,0,"Float") ;store 0.8 as the value
+{% endhighlight %}