CoreText crashes when run in multiple threads

Question

I have a very weird problem with core text, which sometimes randomly and sometimes reproducibly crashes my application. I use it to lay out and render a couple of pages. I do th

Answer 1

fix from me :-) no crash anymore

old code

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:aText];
[attributedString addAttribute:(id)kCTFontAttributeName value:(id)aFontRef range:NSMakeRange(0, [aText length])];

CTFramesetterRef framesetterRef = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);

new code

CFMutableAttributedStringRef attributedStringRef = CFAttributedStringCreateMutable(nil, 0);
CFAttributedStringBeginEditing(attributedStringRef);
CFAttributedStringReplaceString(attributedStringRef, CFRangeMake(0, 0), (CFStringRef)aText);
CFAttributedStringSetAttribute(attributedStringRef, CFRangeMake(0, aText.length), kCTFontAttributeName, aFontRef);
CFAttributedStringEndEditing(attributedStringRef);

CTFramesetterRef framesetterRef = CTFramesetterCreateWithAttributedString(attributedStringRef);