21.3.7.9, p4 requires the operator to set failbit, not badbit, on failure. This came up while I was gathering background for c++std-lib-17241.
$ cat ~/tmp/t.cpp && g++ ~/tmp/t.cpp -static && ./a.out #include <cassert> #include <cstdio> #include <string> #include <strstream> int main () { char buf [3]; std::ostrstream os (buf, sizeof (buf)); os << std::string ("1234"); std::printf ("state = %c%c%c (expected --?)\n", os.rdstate () & os.badbit ? 'B' : '-', os.rdstate () & os.eofbit ? 'E' : '-', os.rdstate () & os.failbit ? 'F' : '-'); std::fflush (stdout); assert (!(os.rdstate () & os.badbit)); } In file included from /usr/local/gcc-4.1.0/lib/gcc/sparc-sun-solaris2.9/4.1.0/../../../../include/c++/4.1.0/backward/strstream:51, from /nfs/b20/sebor/tmp/t.cpp:4: /usr/local/gcc-4.1.0/lib/gcc/sparc-sun-solaris2.9/4.1.0/../../../../include/c++/4.1.0/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated. state = B-- (expected --?) Assertion failed: !(os.rdstate () & os.badbit), file /nfs/b20/sebor/tmp/t.cpp, line 21 Abort (core dumped) -- Summary: std::operator<<(ostream&, string) sets badbit instead of failbit on failure Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sebor at roguewave dot com GCC build triplet: all GCC host triplet: all GCC target triplet: all http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28103