PR libstdc++/53984 handle exceptions in basic_istream::sentry
PR libstdc++/53984
* include/bits/basic_ios.h (basic_ios::_M_setstate): Adjust comment.
* include/bits/istream.tcc (basic_istream::sentry): Handle exceptions
during construction.
* include/std/istream: Adjust comments for formatted input functions
and unformatted input functions.
* testsuite/27_io/basic_fstream/53984.cc: New.
* testsuite/27_io/basic_istream/sentry/char/53984.cc: New.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@250545 138bc75d-0d04-0410-961f-82ee72b054a4