https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85343
Bug ID: 85343
Summary: Overload __throw_ios_failure to allow passing errno
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
The standard says "When throwing ios_base::failure exceptions, implementations
should provide values of ec that identify the specific reason for the failure."
We currently always use an error_code containing io_errc::stream.
We can probably only expect errno to be set for filebuf operations, and in
practice only for failed reads. Failed writes from basic_filebuf::overflow
return -1 which might cause a stream object to set failbit and then throw, but
at that point we're too far away from the write to know if errno can be relied
on or not.
