GCC Debugging/g++/Warnings

friend declaration 'FUNCTION' declares a non-template function

 * Message found in GCC version 4.5.1
 * usually paired with message:
 * note: (if this is not what you intended, make sure the function template has already been declared and add <> after the function name here)

Possible fix?

ISO C++ says that these are ambiguous
ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second
 * Message found in GCC versions ?
 * possibly a custom defined type cast is interfering with another cast inside a class definition

multi-character character constant

 * Message found in GCC versions 4.4.3, 4.5.1
 * sometimes paired with the warning: "overflow in implicit constant conversion"
 * possibly from using a forward slash instead of a backslash in a character assignment.

null argument where non-null required

 * Message found in GCC versions ?
 * you're passing a null argument to a string function