https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85222
Bug ID: 85222
Summary: [7/8 Regression] ABI breakage of __throw_ios_failure
by r244498
Product: gcc
Version: 7.3.1
Status: UNCONFIRMED
Keywords: ABI
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
CC: redi at gcc dot gnu.org
Blocks: 66145
Target Milestone: ---
A program compiled with a GCC defaulting to the old ABI
(like GCC 4.8) now fails to run with a dual-ABI libstdc++:
#include <iostream>
#include <fstream>
using namespace std;
int main ()
{
std::ifstream pstats;
pstats.exceptions(ifstream::failbit | ifstream::badbit | ifstream::eofbit);
try {
printf("\n Opening file : /proc/0/stat ");
pstats.open("/proc/0/stat");
}
catch(ifstream::failure e)
{
printf("\n!!Caught ifstream exception!!\n");
if(pstats.is_open()) {
pstats.close();
}
}
return 0;
}
tmp> g++-4.8 t.C
tmp> ./a.out
terminate called after throwing an instance of
'std::ios_base::failure[abi:cxx11]'
what(): basic_ios::clear: iostream error
Aborted (core dumped)
tmp> LD_LIBRARY_PATH=/space/rguenther/install/gcc-6.4/lib64 ./a.out
Opening file : /proc/0/stat
!!Caught ifstream exception!!
This is because of the documented change of throwing the C++11 errors from
the libraries I/O routines in the attempt to fix PR66145. This in turn
breaks any old programs trying to catch such exceptions thrown by the
library.
__throw_ios_failure, while being exported, isn't called by the testcase
above but just by libstdc++ but the program is rightfully expecting to
be able to catch ifstream::failure.
A workaround is to use a libstdc++ built with --disable-libstdcxx-dual-abi
but that of course makes it incompatible with any programs using the new ABI.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145
[Bug 66145] [5/6/7 Regression] std::ios_base::failure objects thrown from
libstdc++.so use old ABI
