Description:
------------
It would be nice if the description of the result in the manual page on mysqli::__construct() could say something like that the result "is of type mysqli, even if the connection fails (i.e. never null)"; and somewhere (maybe with the result) that errno should be checked to determine whether the operation failed.

An early example with a note that one doesn't do things the C/C++ way would also be enlightening.

This would assist those of us coming from systems in which  failures of constructors commonly return NULL and failures of functions commonly return FALSE - very common in libraries for C and languages derived from C. 

[I can't be alone in being a little slow to realize that you've done thing in a better way, at the price that I've some extra work to do in converting code to PHP+mysqli :-) ]

Much the same applies to all other manual pages on any constructor or method with an errno (or in this case connect_errno) that should routinely be checked - so (apologies!) this is a meta-comment applying to many of the manual's pages. [My own old scars tell me that I'd requesting a substantial documentation-editing effort.]