We see a different exception in the latter core:
(gdb) p what $1 = {static npos = <optimized out>, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x7f96980129c8 "basic_string::_S_construct null not valid"}}
We see a different exception in the latter core:
(gdb) p what allocator< char>> = {<__gnu_ cxx::new_ allocator< char>> = {<No data fields>}, <No data fields>}, string: :_S_construct null not valid"}}
$1 = {static npos = <optimized out>, _M_dataplus = {<std::
_M_p = 0x7f96980129c8 "basic_