__clang_analyzer__的重要性

Question

What is the importance of clang_analyzer as without using this I see analyzer shouting a leak on the below piece of code.

#ifndef __clang_analyzer__
CGPathRef pathWithRoundRect(CGRect iRect, CGFloat iRadius) {
    CGMutablePathRef returnVal = CGPathCreateMutable();
    CGPathMoveToPoint();
    CGPathAddArcToPoint();
    CGPathAddArcToPoint();
    CGPathAddArcToPoint();
    CGPathAddArcToPoint();
    CGPathCloseSubpath(returnVal);
    return returnVal;
}
#endif

Answer 1

__clang_analyzer__ is a macro, defined when the program is compiled for the analyzer (see the Clang User's Manual ).

When it's defined, the code between #ifndef and #endif isn't being compiled, which means that the analyzer doesn't see it and can't tell you about the owned CGMutablePath that you're returning from a function whose name doesn't indicate it returns an owning reference.

You should consider adding create to the beginning of the function name.