[committed] libstdc++: Do not declare strtok for C++26 freestanding (P2937R0)

[Jonathan Wakely]

Tested x86_64-linux. Pushed to trunk.

-- >8 --

This was recently approved for C++26.

We should define the __cpp_lib_freestanding_cstring macro in <string.h>
as well as <cstring>, but we do not currently install our own <string.h>
for most targets.

libstdc++-v3/ChangeLog:

        * include/bits/version.def (freestanding_cstring): Add.
        * include/bits/version.h: Regenerate.
        * include/c_compatibility/string.h (strtok): Do not declare for
        C++26 freestanding.
        * include/c_global/cstring (strtok): Likewise.
        * testsuite/21_strings/headers/cstring/version.cc: New test.
---
 libstdc++-v3/include/bits/version.def         |  9 ++
 libstdc++-v3/include/bits/version.h           | 89 +++++++++++--------
 libstdc++-v3/include/c_compatibility/string.h |  2 +
 libstdc++-v3/include/c_global/cstring         |  5 +-
 .../21_strings/headers/cstring/version.cc     | 19 ++++
 5 files changed, 84 insertions(+), 40 deletions(-)
 create mode 100644 libstdc++-v3/testsuite/21_strings/headers/cstring/version.cc

diff --git a/libstdc++-v3/include/bits/version.def 
b/libstdc++-v3/include/bits/version.def
index 1c49ecea25e..605708dfee7 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1366,6 +1366,15 @@ ftms = {
   };
 };
 
+ftms = {
+  name = freestanding_cstring;
+  values = {
+    v = 202311;
+    // This is a C++26 feature, but we support it in C++23.
+    cxxmin = 23;
+  };
+};
+
 ftms = {
   name = freestanding_expected;
   values = {
diff --git a/libstdc++-v3/include/bits/version.h 
b/libstdc++-v3/include/bits/version.h
index a61d482c662..cacd9375cab 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -1653,6 +1653,17 @@
 #undef __glibcxx_want_freestanding_array
 
 // from version.def line 1370
+#if !defined(__cpp_lib_freestanding_cstring)
+# if (__cplusplus >= 202100L)
+#  define __glibcxx_freestanding_cstring 202311L
+#  if defined(__glibcxx_want_all) || 
defined(__glibcxx_want_freestanding_cstring)
+#   define __cpp_lib_freestanding_cstring 202311L
+#  endif
+# endif
+#endif /* !defined(__cpp_lib_freestanding_cstring) && 
defined(__glibcxx_want_freestanding_cstring) */
+#undef __glibcxx_want_freestanding_cstring
+
+// from version.def line 1379
 #if !defined(__cpp_lib_freestanding_expected)
 # if (__cplusplus >= 202100L) && (__cpp_lib_expected)
 #  define __glibcxx_freestanding_expected 202311L
diff --git a/libstdc++-v3/include/c_compatibility/string.h 
b/libstdc++-v3/include/c_compatibility/string.h
index 1d9e0d2a9bd..06529af057c 100644
--- a/libstdc++-v3/include/c_compatibility/string.h
+++ b/libstdc++-v3/include/c_compatibility/string.h
@@ -50,7 +50,9 @@ using std::strpbrk;
 using std::strrchr;
 using std::strspn;
 using std::strstr;
+#if _GLIBCXX_HOSTED || __cplusplus <= 202302L
 using std::strtok;
+#endif
 using std::memset;
 using std::strerror;
 using std::strlen;
diff --git a/libstdc++-v3/include/c_global/cstring 
b/libstdc++-v3/include/c_global/cstring
index d0a129ac802..f39aae1c82e 100644
--- a/libstdc++-v3/include/c_global/cstring
+++ b/libstdc++-v3/include/c_global/cstring
@@ -38,7 +38,8 @@
 
 #pragma GCC system_header
 
-#include <bits/c++config.h>
+#define __glibcxx_want_freestanding_cstring
+#include <bits/version.h>
 #include <string.h>
 
 #ifndef _GLIBCXX_CSTRING
@@ -90,7 +91,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   using ::strncmp;
   using ::strncpy;
   using ::strspn;
+#if _GLIBCXX_HOSTED || __cplusplus <= 202302L
   using ::strtok;
+#endif
   using ::strxfrm;
   using ::strchr;
   using ::strpbrk;
diff --git a/libstdc++-v3/testsuite/21_strings/headers/cstring/version.cc 
b/libstdc++-v3/testsuite/21_strings/headers/cstring/version.cc
new file mode 100644
index 00000000000..06735e86a76
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/headers/cstring/version.cc
@@ -0,0 +1,19 @@
+// { dg-do compile { target c++26 } }
+// { dg-add-options no_pch }
+
+#include <cstring>
+
+#ifndef __cpp_lib_freestanding_cstring
+# error "Feature test macro for freestanding <cstring> is missing in <cstring>"
+#elif __cpp_lib_freestanding_cstring < 202311L
+# error "Feature test macro for freestanding <cstring> has wrong value in 
<cstring>"
+#endif
+
+#undef __cpp_lib_freestanding_cstring
+#include <version>
+
+#ifndef __cpp_lib_freestanding_cstring
+# error "Feature test macro for freestanding <cstring> is missing in <version>"
+#elif __cpp_lib_freestanding_cstring < 202311L
+# error "Feature test macro for freestanding <cstring> has wrong value in 
<version>"
+#endif
-- 
2.42.0