Question

I am getting an error that I don’t understand how to fix. The error is:

Sending 'CGFloat' (aka 'float') to parameter of incompatible type 'CGFloat *' (aka 'float *'); 

For line:

[xlabel.text drawAtPoint:CGPointMake(labelRect.origin.x, labelRect.origin.y) 
                forWidth:labelRect.size.width 
                withFont:myFont 
             minFontSize:5.0 
          actualFontSize:myFont.pointSize 
           lineBreakMode:UILineBreakModeWordWrap 
      baselineAdjustment:UIBaselineAdjustmentAlignCenters];

the error points to actualFontSize:myFont.pointSize. myFont is a UIFont. I set it like so: UIFont *myFont = [UIFont systemFontOfSize:17.0];

What does that error mean and any ideas on how to fix it?

Answer 1

From the docs:

actualFontSize On input, a pointer to a floating-point value. On
return, this value contains the actual font size that was used to
render the string.

Which means that you have to pass in a pointer, by referencing a variable. To do so you use the ampersand operator &

Example:

CGFloat outSize = 0;
[xlabel.text drawAtPoint:CGPointMake(labelRect.origin.x, labelRect.origin.y) 
                forWidth:labelRect.size.width 
                withFont:myFont 
             minFontSize:5.0 
          actualFontSize:&outSize 
           lineBreakMode:UILineBreakModeWordWrap 
      baselineAdjustment:UIBaselineAdjustmentAlignCenters];
NSLog(@"%f", outSize);

drawAtPoint: will set the value that outSize points to and so you can print the result.
The reason for this here is, that you can only return 1 value in C via return statement. To get multiple results, you can pass in pointers to allow the method to set additional results.