commit bffd3c8d94b7978d296df4b0e2fa77cc5887efe6 Author: Tom Honermann Date: Sat Feb 13 07:53:34 2021 -0500 P0482R6 char8_t: declare std::c8rtomb and std::mbrtoc8 if provided by the C library. This change completes implementation of the C++20 proposal P0482R6 by adding declarations of std::c8rtomb() and std::mbrtoc8() if provided by the C library. Autoconf changes determine if the C library declares c8rtomb and mbrtoc8 at global scope when uchar.h is included and compiled with -fchar8_t; _GLIBCXX_USE_UCHAR_CHAR8_T is defined if so. The header re-declares these functions in the std namespace only if available and the C++20 __cpp_char8_t feature test macro is defined. A new test is provided. The test passes trivially if the C library does not provide these functions. Otherwise it ensures that the functions are declared when is included and -fchar8_t support is enabled. diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 90ecc4a87a2..355c21a03b5 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -2063,6 +2063,28 @@ AC_DEFUN([GLIBCXX_CHECK_UCHAR_H], [ namespace std in .]) fi + CXXFLAGS="$CXXFLAGS -fchar8_t" + if test x"$ac_has_uchar_h" = x"yes"; then + AC_MSG_CHECKING([for char8_t support in ]) + AC_TRY_COMPILE([#include + char8_t c8; + namespace test + { + using ::c8rtomb; + using ::mbrtoc8; + } + ], + [], [ac_uchar_char8_t=yes], [ac_uchar_char8_t=no]) + else + ac_uchar_char8_t=no + fi + AC_MSG_RESULT($ac_uchar_char8_t) + if test x"$ac_uchar_char8_t" = x"yes"; then + AC_DEFINE(_GLIBCXX_USE_UCHAR_CHAR8_T, 1, + [Define if char8_t functions in should be imported into + namespace std in .]) + fi + CXXFLAGS="$ac_save_CXXFLAGS" AC_LANG_RESTORE ]) diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in index e545488386a..745de9687a4 100644 --- a/libstdc++-v3/config.h.in +++ b/libstdc++-v3/config.h.in @@ -991,6 +991,10 @@ /* Define if obsolescent tmpnam is available in . */ #undef _GLIBCXX_USE_TMPNAM +/* Define if char8_t functions in should be imported into namespace + std in . */ +#undef _GLIBCXX_USE_UCHAR_CHAR8_T + /* Define if utime is available in . */ #undef _GLIBCXX_USE_UTIME diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 6f08b65c8ba..8311419a127 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -19115,6 +19115,45 @@ $as_echo "#define _GLIBCXX_USE_C11_UCHAR_CXX11 1" >>confdefs.h fi + CXXFLAGS="$CXXFLAGS -fchar8_t" + if test x"$ac_has_uchar_h" = x"yes"; then + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for char8_t support in " >&5 +$as_echo_n "checking for char8_t support in ... " >&6; } + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +#include + char8_t c8; + namespace test + { + using ::c8rtomb; + using ::mbrtoc8; + } + +int +main () +{ + + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_compile "$LINENO"; then : + ac_uchar_char8_t=yes +else + ac_uchar_char8_t=no +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + else + ac_uchar_char8_t=no + fi + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_uchar_char8_t" >&5 +$as_echo "$ac_uchar_char8_t" >&6; } + if test x"$ac_uchar_char8_t" = x"yes"; then + +$as_echo "#define _GLIBCXX_USE_UCHAR_CHAR8_T 1" >>confdefs.h + + fi + CXXFLAGS="$ac_save_CXXFLAGS" ac_ext=c ac_cpp='$CPP $CPPFLAGS' diff --git a/libstdc++-v3/include/c_compatibility/uchar.h b/libstdc++-v3/include/c_compatibility/uchar.h index 1fe8a22f78a..21812bb44b4 100644 --- a/libstdc++-v3/include/c_compatibility/uchar.h +++ b/libstdc++-v3/include/c_compatibility/uchar.h @@ -33,6 +33,11 @@ #ifdef _GLIBCXX_NAMESPACE_C +#if _GLIBCXX_USE_CHAR8_T && _GLIBCXX_USE_UCHAR_CHAR8_T +using std::mbrtoc8; +using std::c8rtomb; +#endif + #if _GLIBCXX_USE_C11_UCHAR_CXX11 using std::mbrtoc16; using std::c16rtomb; diff --git a/libstdc++-v3/include/c_global/cuchar b/libstdc++-v3/include/c_global/cuchar index 57047d74218..aab62e57bc8 100644 --- a/libstdc++-v3/include/c_global/cuchar +++ b/libstdc++-v3/include/c_global/cuchar @@ -48,10 +48,34 @@ #include #include -#if _GLIBCXX_USE_C11_UCHAR_CXX11 +#if _GLIBCXX_USE_C11_UCHAR_CXX11 || _GLIBCXX_USE_CHAR8_T #include +#endif + + +// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library. +#if _GLIBCXX_USE_CHAR8_T && _GLIBCXX_USE_UCHAR_CHAR8_T + +#undef mbrtoc8 +#undef c8rtomb + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + using ::mbrtoc8; + using ::c8rtomb; + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace std + +#endif // _GLIBCXX_USE_CHAR8_T && _GLIBCXX_USE_UCHAR_CHAR8_T + + +#if _GLIBCXX_USE_C11_UCHAR_CXX11 + // Get rid of those macros defined in in lieu of real functions. #undef mbrtoc16 #undef c16rtomb diff --git a/libstdc++-v3/include/c_std/cuchar b/libstdc++-v3/include/c_std/cuchar index 7ce413e1bb0..13d8b773c49 100644 --- a/libstdc++-v3/include/c_std/cuchar +++ b/libstdc++-v3/include/c_std/cuchar @@ -48,10 +48,35 @@ #include #include -#if _GLIBCXX_USE_C11_UCHAR_CXX11 +#if _GLIBCXX_USE_C11_UCHAR_CXX11 || _GLIBCXX_USE_CHAR8_T #include +#endif + + +// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library. +#if _GLIBCXX_USE_CHAR8_T && _GLIBCXX_USE_UCHAR_CHAR8_T + +// Get rid of those macros defined in in lieu of real functions. +#undef mbrtoc8 +#undef c8rtomb + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + using ::mbrtoc8; + using ::c8rtomb; + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace std + +#endif // _GLIBCXX_USE_CHAR8_T && _GLIBCXX_USE_UCHAR_CHAR8_T + + +#if _GLIBCXX_USE_C11_UCHAR_CXX11 + // Get rid of those macros defined in in lieu of real functions. #undef mbrtoc16 #undef c16rtomb diff --git a/libstdc++-v3/testsuite/21_strings/headers/cuchar/functions_std.cc b/libstdc++-v3/testsuite/21_strings/headers/cuchar/functions_std.cc new file mode 100644 index 00000000000..192b5a0481d --- /dev/null +++ b/libstdc++-v3/testsuite/21_strings/headers/cuchar/functions_std.cc @@ -0,0 +1,12 @@ +// { dg-do compile } +// { dg-options "-fchar8_t" } + +#include + +namespace gnu +{ +#if _GLIBCXX_USE_UCHAR_CHAR8_T + using std::mbrtoc8; + using std::c8rtomb; +#endif +}