Re: [Bug-ddrescue] Cannot compile with uClibc-ng

[Rosen Penev]

On Mon, Jul 22, 2019 at 6:08 PM Rosen Penev <address@hidden> wrote:
>
> On Mon, Jul 22, 2019 at 4:52 PM Rosen Penev <address@hidden> wrote:
> >
> > On Mon, Jul 22, 2019 at 1:58 PM Antonio Diaz Diaz <address@hidden> wrote:
> > >
> > > Rosen Penev wrote:
> > > >>>> IMO this is a bug in uClibc-ng
> > > >>> Even so, it might still make sense to work around it.
> > > >>
> > > >> I don't see how this can be done. Using plain 'fgetc' instead of
> > > >> 'std::fgetc' will fail with conforming libc implementations.
> > > > I don't really do C++, but this is one of the ways a similar issue was
> > > > fixed:
> > > > https://github.com/facebook/folly/commit/b2cecfb5ced32cac372cfe6c5ac1935365b5dd60
> > >
> > > That fix is for std::remainder, which is C++11 and therefore not present
> > > in previous versions of the standard. I made a similar fix for
> > > std::snprintf, which was introduced in C99 and was therefore absent from
> > > C++98.
> > >
> > > The case of std::fgetc is different. 'fgetc' is in C since the dawn of
> > > time and therefore std::fgetc must be provided by any compliant C++
> > > library. IMO this bug should not be worked around, but fixed in uClibc-ng.
> > Interesting...
> >
> > So the setup was uClibc-ng as the libc and uClibc++ as the libc++. If
> > I swap out uClibc++ for libstdcpp, it works.
> >
> > OTOH, if I swap out uClibc-ng for musl or something, it also works.
> >
> > No idea which problem should be fixed. Looking at
> > https://git.busybox.net/uClibc++/tree/include/cstdio?id=6ff572f21e2ce654d0c49dca3c64c49625fd266a#n34
> > , I don't see a problem.
> >
> > Looking at 
> > https://gcc.gnu.org/onlinedocs/gcc-4.6.3/libstdc++/api/a00832_source.html
> > , it seems libstdcpp uses #undef on all the functions before including
> > them.
> Adding #undef <function> everywhere worked.
Zombie revive:

I've concluded that the libc++ is the issue. I've submitted and tested
a patch that works:
http://lists.busybox.net/pipermail/uclibc/2019-September/049288.html .
It was accepted.

The actual header seems to be based on an old version of GNU libstdcpp.
> > >
> > > Best regards,
> > > Antonio.