[Libguestfs] [PATCH 0/3] Use __attribute__((cleanup(...)))

This patch series changes a small part of the library to use __attribute__((cleanup(...))) to automatically free memory when pointers go out of the current scope. In general terms this seems to be a small win although you do have to use it carefully. For functions where you can completely get rid of the "exit code paths", it can simplify things. For a good example, see the 'inspect-icon.c:icon_windows_xp' function before and after the change. For most functions there is no change or a minor simplification. It can however cause problems if you accidentally put a CLEANUP_FREE annotation on a pointer which is actually returned from the function, or if you explicitly free something. If we make this change, then the library will leak memory when compiled with something that isn't GCC/LLVM. It's likely we have other dependencies on GCC, since we've never seriously tried compiling the library with any other compiler. References ---------- GCC manual: http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html Previous attempt: https://www.redhat.com/archives/libguestfs/2013-January/thread.html#00068