Which version of gcc is on Mountain Lion?

Solution 1:

Mountain Lion doesn't ship with any GCC, but you can install GCC 4.7 . I have done this on my machine.

Solution 2:

Apple doesn't ship compilers with their App Store OS versions (Lion and now Mountain Lion) so the answer is none.

It does provide an llvm-gcc binary that serves as gcc as part of Xcode and the developer tools. This is a free download and you can use it to bootstrap to whatever version of gcc you please if the shipping version isn't to your liking.

Here is gcc version that ships with Xcode v4.3.3

Air:~ mike$ which gcc
/usr/bin/gcc
Air:~ mike$ gcc --version
i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.