PR libstdc++/94854
* include/bits/basic_string.tcc: Update comment about explicit
instantiations.
Committed to master as obvious. Backports to follow.
commit 8f1591763fd50b143af0dc1770741f326a97583a
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Apr 29 18:57:34 2020 +0100
libstdc++: Fix outdated comment about std::string instantiations (PR 94854)
PR libstdc++/94854
* include/bits/basic_string.tcc: Update comment about explicit
instantiations.
diff --git a/libstdc++-v3/include/bits/basic_string.tcc
b/libstdc++-v3/include/bits/basic_string.tcc
index e78bb2c14b3..e370f439390 100644
--- a/libstdc++-v3/include/bits/basic_string.tcc
+++ b/libstdc++-v3/include/bits/basic_string.tcc
@@ -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
