[PATH 3/3] libstdc++: Add std::advance ostreambuf_iterator overload

[Jonathan Wakely]

On 09/09/20 22:12 +0200, François Dumont via Libstdc++ wrote:
>libstdc++: Add std::advance overload for ostreambuf_iterator
>
>Implement std::advance overload for ostreambuf_iterator using 
>basic_streambuf
>pubseekof.
>
>libstdc++-v3/ChangeLog:
>
>Â Â Â Â Â Â Â  * include/bits/streambuf_iterator.h (ostreambuf_iterator): Add
>Â Â Â Â Â Â Â  std::advance friend declaration.
>Â Â Â Â Â Â Â  (advance(ostreambuf_iterator<>&, _Distance)): New.
>Â Â Â Â Â Â Â  * testsuite/25_algorithms/advance/ostreambuf_iterator/char/1.cc:
>Â Â Â Â Â Â Â  New test.
>Â Â Â Â Â Â Â  * 
>testsuite/25_algorithms/advance/ostreambuf_iterator/char/1_neg.cc:
>Â Â Â Â Â Â Â  New test.
>Â Â Â Â Â Â Â  * testsuite/25_algorithms/advance/ostreambuf_iterator/char/2.cc:
>Â Â Â Â Â Â Â  New test.
>Â Â Â Â Â Â Â  * 
>testsuite/25_algorithms/advance/ostreambuf_iterator/char/2_neg.cc:
>Â Â Â Â Â Â Â  New test.
>
>Tested under Linux x85_64.
>
>Ok to commit ?

I think relying on seeking here is a bad idea for the same reason as
in my previous email. We don't know what seek does for an arbitrary
derived streambuf, or even if it is possible at all.