warning ???

/home/rkotler/workspace/....: error: co
nstant expression evaluates to -1 which cannot be narrowed to type 'unsigned int
' [-Wc++11-narrowing]

Shows as a warning but is really an error to the compiler

It appears as an error (note the "error:") -- such constructs are
ill-formed in C++11. If you're referring to the "[-Wc++11-narrowing]", that
indicates that this error can be disabled with "-Wno-c++11-narrowing", as a
compatibility measure.

That's our "DefaultError" marking; it's basically equivalent to specifying
"-Werror=c++11-narrowing" by default. We use it here because we really
don't want people to write code that isn't well-formed by accident.