Question

I am converting my project to ARC and Xcode thinks there is a memory leak here, does anyone see anything wrong with this? I didn’t write this code so I am not familiar with C calls.

- (NSString*) URLEscaped
{

    NSString *encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(
                                NULL,
                                (CFStringRef)self,
                                NULL,
                                (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                kCFStringEncodingUTF8);

    return encodedString;

}

Answer 1

From the docs:

There are many ways in which you can get a reference to an object
using Core Foundation. In line with the Core Foundation ownership
policy, you need to know whether or not you own an object returned by
a function so that you know what action to take with respect to memory
management. Core Foundation has established a naming convention for
its functions that allows you to determine whether or not you own an
object returned by a function. In brief, if a function name contains
the word "Create" or "Copy", you own the object. If a function name
contains the word "Get", you do not own the object.

Yes, you’re leaking a CFString there.