libstdc++: Fix outdated comment about std::string instantiations (PR 94854)

PR libstdc++/94854
	* include/bits/basic_string.tcc: Update comment about explicit
	instantiations.
This commit is contained in:
Jonathan Wakely 2020-04-29 18:57:34 +01:00
parent 0c8217b16f
commit 8f1591763f
2 changed files with 11 additions and 5 deletions

View File

@ -1,3 +1,9 @@
2020-04-29 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/94854
* include/bits/basic_string.tcc: Update comment about explicit
instantiations.
2020-04-28 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/91480

View File

@ -1609,11 +1609,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Inhibit implicit instantiations for required instantiations,
// which are defined via explicit instantiations elsewhere.
#if _GLIBCXX_EXTERN_TEMPLATE
// The explicit instantiations definitions in src/c++11/string-inst.cc
// are compiled as C++14, so the new C++17 members aren't instantiated.
// Until those definitions are compiled as C++17 suppress the declaration,
// so C++17 code will implicitly instantiate std::string and std::wstring
// as needed.
// The explicit instantiation definitions in src/c++11/string-inst.cc and
// src/c++17/string-inst.cc only instantiate the members required for C++17
// and earlier standards (so not C++20's starts_with and ends_with).
// Suppress the explicit instantiation declarations for C++20, so C++20
// code will implicitly instantiate std::string and std::wstring as needed.
# if __cplusplus <= 201703L && _GLIBCXX_EXTERN_TEMPLATE > 0
extern template class basic_string<char>;
# elif ! _GLIBCXX_USE_CXX11_ABI