gnu /
gcc /
2c2df024df3aa6248f92203df9c1051b5f1fe5f8 libstdc++: Merge bind_front and bind_back binders
The _Bind_front and _Bind_back class templates are now merged into a single
_Binder implementation that accepts _Back as a template parameter. This makes
the bind_back implementation available in C++20 mode, allowing it to be used
for range adaptor closures.
With zero bound arguments, bind_back and bind_front have equivalent
functionality. Consequently, _Bind_back_t now produces the same type as
bind_front (_Binder<false, _Fd>). A simple copy of the functor cannot be
returned in this case, as it would visibly affect overload resolution
(see included test cases).
We also replace std::invoke in internal functions, with std::__invoke.
libstdc++-v3/ChangeLog:
* include/std/functional: (std::_Indexed_bound_arg): Fixed
indentation.
(__Bound_arg_storage::_S_apply_front)
(__Bound_arg_storage::_S_apply_front): Merged into _S_apply.
(__Bound_arg_storage::_S_apply): Merged above, add _Back template
parameter, replace std::invoke with std::__invoke.
(std::_Bind_front): Renamed to std::_Binder and add _Back
template parameter.
(std::_Binder): Renamed from std::_Bind_front.
(_Binder::_Result_t, _Binder::_S_noexcept_invoke): Define.
(_Binder::operator()): Use _Result_t and _S_noexcept_invoke.
(_Binder::_S_call): Handle zero args specially, replace std::invoke
with std::__invoke.
(std::_Bind_front_t, std::_Bind_back_t): Defined in terms
of _Binder.
(std::_Bind_back): Merged into _Binder.
* testsuite/20_util/function_objects/bind_back/1.cc: New tests.
* testsuite/20_util/function_objects/bind_back/111327.cc: Updated
error messages.
* testsuite/20_util/function_objects/bind_front/1.cc: New tests.
* testsuite/20_util/function_objects/bind_front/111327.cc: Updated
error messages.
Reviewed-by: Patrick Palka <ppalka@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
5 files changed
