On 22/05/2023 22:55, Jonathan Wakely wrote:
On Mon, 22 May 2023 at 21:51, François Dumont via Libstdc++
<libstd...@gcc.gnu.org <mailto:libstdc%2b...@gcc.gnu.org>> wrote:
I was thinking that it might be nice to get rid of
predefined_ops.h content.
So here is a start with __negate. Drawback is that stl_algo.h has to
include <functional>.
We definitely don't want that. std::not_fn could be move to its own
header.
But I'm not sure this is a good change anyway, as we can't do it
unconditionally. Pre-C++17 code would still be using the
predefined_ops.h function objects, so we can't remove that code. And
we'll get template bloat from instantiating the algos twice, once with
the old function objects and once with std::not_fn.
True, what do you advise then ? Should I just forget about it ?
Introduce a std::__not_fn for pre-C++17 ?
I am studying this last proposal, let me know if it is just impossible
or a waste of time.
For now I just get rid of stl_algo.h include in
<functional> to rather use stl_algobase.h. But maybe it would be
better
to also isolate std::not_fn in a dedicated header file so that
stl_algo.h do not have to include all <functional>.
libstdc++: Replace __gnu_cxx::__ops::__negate with std::not_fn
Replace the internal __gnu_cxx::__ops::__negate function and
associated
__gnu_cxx::__ops::_Iter_negate by the C++17 std::not_fn.
libstdc++-v3/ChangeLog:
* include/bits/predefined_ops.h: Include <version>.
No, please don't include <version> anywhere. If you do that, it means
<functional> now defines every feature test macro in the entire
library, which makes it look like you can get smart pointers and
ranges and constexpr math all from <functional>.
Ok, I wasn't aware about the interest of <version>. I see now, limited
to user code.
I'm testing only the move of std::search to stl_algobase.h to avoid
stl_algo.h include in <functional>. I'll submit it later.
