Re: [boost] [iostreams] Patch for mapped_file.cpp.

Hi.

I'm attaching a patch for libs/iostreams/src/mapped_file.cpp which corrects the mapped_file_source::operator!() operator.

It seems to have been erroneously returning true in case the implementation object exists but has its error_ flag set.

Since there has been no response to this patch report and its a really simple one I went ahead and committed it. Best regards, Jurko Gospodnetić