[MacRuby-devel] MacRuby pointers and Obj-C function returning a value by reference

kwicher at wichry.net kwicher at wichry.net
Mon Jan 21 14:08:48 PST 2013


I am trying to implement the following method of NSAttributedString in Macruby:

- (id)attribute:(NSString *)attributeName atIndex:(NSUInteger)index effectiveRange:(NSRangePointer)aRange

As by definition, it `Returns the value for an attribute with a given name of the character at a given index, and by reference the range over which the attribute applies.`

OK, so I need a pointer to NSRange, which I set up as follows:

    range=Pointer.new("{_NSRange=QQ}")[0]

It seems to be fine as `range.class` => `NSRange`.

However, when I execute the method: 

    font=txtStor.attribute(NSFontAttributeName,atIndex:index,effectiveRange:range)

my `range` is always `#<NSRange location=0 length=0>`. Also, `p range` gives me `#<NSRange location=0 length=0>`.

Any ideas how to implement this correctly?

Thanks
K


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