[Bug libstdc++/81395] [5/6/7/8 Regression] basic_filebuf::overflow recurses and overflows stack

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81395

--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Author: redi
Date: Tue Jul 18 23:39:34 2017
New Revision: 250328

URL: https://gcc.gnu.org/viewcvs?rev=250328&root=gcc&view=rev
Log:
PR libstdc++/81395 fix crash when write follows large read

        PR libstdc++/81395
        * include/bits/fstream.tcc (basic_filebuf::xsgetn): Don't set buffer
        pointers for write mode after reading.
        * testsuite/27_io/basic_filebuf/sgetn/char/81395.cc: New.

Added:
    trunk/libstdc++-v3/testsuite/27_io/basic_filebuf/sgetn/char/81395.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/fstream.tcc