Question

I’m using gdb 6.3.50, the one that comes with Xcode 4.4.1. It seems to get confused by my attempts to call class on an object in the debugger.

(gdb) po [JSONObject class]
A syntax error in expression, near `]'.

I assume it’s getting tripped up by the word “class”, which must be some kind of reserved symbol, perhaps because I’m working in Objective-C++. Certainly, I can prod it into an error with identical wording if I try to use some other C keyword:

(gdb) po [JSONObject struct]
A syntax error in expression, near `]'.

There’s nothing wrong with the object itself, it seems, because gdb can call other methods on it:

(gdb) po [JSONObject objectForKey:@"UTIMESTAMP"]
<__NSCFArray 0x89c9b0>( ...(etc.>)

Is there some construct, or symbol, or something, that I can put in the command line, to force gdb to treat “class” as just a selector?

Answer 1

Try using the Objective-C messenger functions directly:

po (id)objc_msgSend(JSONObject, @selector(class))