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AGS Pointers for Dummies: Difference between revisions
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==Working With Managed Types== | ==Working With Managed Types== | ||
You can work with these managed types through pointers. You define a pointer by typing the name of the managed data type, then a space, an | You can work with these managed types through pointers. You define a pointer by typing the name of the managed data type, then a space, an asterisk (*)<sup>6</sup>, and finally the name of the pointer. So, if we want to create a GUI pointer (this is expressed as GUI*) called GUIPointer, we could type the following: | ||
GUI *GUIPointer; | GUI *GUIPointer; | ||
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This creates a pointer that can ''point'' to any GUI stored in the memory. However, until it is assigned a value, it is an empty, or ''null'' pointer. We'll first discuss how to assign pointers a value, then we'll discuss null pointers. | This creates a pointer that can ''point'' to any GUI stored in the memory. However, until it is assigned a value, it is an empty, or ''null'' pointer. We'll first discuss how to assign pointers a value, then we'll discuss null pointers. | ||
<sup>6</sup>'''<font size="1">The | <sup>6</sup>'''<font size="1">The asterisk doesn't necessarily have to be attached to the name of the pointer, such as "GUI *MyGUIPointer", it can also be attached to the data type itself, such as "GUI* MyGUIPointer". However, it will still be compiled as if it is attached to the name of the pointer, not the data type, so if you define multiple pointers at once, you will still need an asterisk for each pointer.</font>''' | ||
==Array of Pointers== | ==Array of Pointers== | ||
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GUI *GUIPointer = gMygui; | GUI *GUIPointer = gMygui; | ||
Global pointers can't have an initial value assigned though, so this will only work if you define the pointer inside of a function. When defining more than one pointer of the same type at once, it is necessary to use an | Global pointers can't have an initial value assigned though, so this will only work if you define the pointer inside of a function. When defining more than one pointer of the same type at once, it is necessary to use an asterisk for every pointer. So, if you want MyGUIPointer to point to MYGUI, and OtherGUIPointer to point to OTHERGUI, you can do this: | ||
GUI *MyGUIPOINTER = gMygui, *OtherGUIPointer = gOthergui; | GUI *MyGUIPOINTER = gMygui, *OtherGUIPointer = gOthergui; | ||
If you forget an | If you forget an asterisk then it will try to create a new instance (create a new variable) of the type GUI. AGS doesn't allow the user to create new instances of managed types, so this would crash your game. So, it's always important to remember your asterisks. | ||
==A More Useful Assignment== | ==A More Useful Assignment== | ||