https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81395
--- Comment #19 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Mon Oct 23 17:47:10 2017 New Revision: 254018 URL: https://gcc.gnu.org/viewcvs?rev=254018&root=gcc&view=rev Log: PR libstdc++/81395 fix crash when write follows large read Backport from mainline 2017-07-18 Jonathan Wakely <jwak...@redhat.com> 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: branches/gcc-6-branch/libstdc++-v3/testsuite/27_io/basic_filebuf/sgetn/char/81395.cc Modified: branches/gcc-6-branch/libstdc++-v3/ChangeLog branches/gcc-6-branch/libstdc++-v3/include/bits/fstream.tcc