Re: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd>
Patrick Palka <[email protected]>
| Newsgroups | gmane.comp.gcc.patches,gmane.comp.gcc.libstdc++.devel |
|---|---|
| Message-ID | <24a12bbb-19a0-5329-418a-24cd8a07f2ea@idea> |
On Fri, 31 Jul 2026, Tomasz Kaminski wrote: > > > On Fri, Jul 31, 2026 at 3:14 PM Patrick Palka <[email protected]> wrote: > Tested on x86_64-pc-linux-gnu, does this look OK for trunk and > backports? > > -- >8 -- > > Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's > defined in c++config and thus provided by all headers by default. > > libstdc++-v3/ChangeLog: > > * include/std/iosfwd: Provide feature-test macros > __cpp_lib_spanstream and __cpp_lib_syncbuf. > * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values > of these FTMs. > --- > libstdc++-v3/include/std/iosfwd | 4 ++++ > libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc | 8 ++++++++ > 2 files changed, 12 insertions(+) > > diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd > index 1d5e684b53bb..511b2f3a23f1 100644 > --- a/libstdc++-v3/include/std/iosfwd > +++ b/libstdc++-v3/include/std/iosfwd > @@ -39,6 +39,10 @@ > > #include <bits/requires_hosted.h> // iostreams > > +#define __glibcxx_want_spanstream > +#define __glibcxx_want_syncbuf > +#include <bits/version.h> > + > /** > * @defgroup io I/O > * > diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc > index 8d9501f42ef4..f39a0b95a3d6 100644 > --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc > +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc > @@ -3,6 +3,14 @@ > > #include <iosfwd> > > +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L > +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" > +#endif > > I would test that __cpp_lib_char8_t is defined when you include this header, even > if it is for all headers. Sure: -- >8 -- Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2 Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Tested on x86_64-pc-linux-gnu, does this look OK for trunk and backports? -- >8 -- Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2 Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Tested on x86_64-pc-linux-gnu, does this look OK for trunk and backports? -- >8 -- Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2 Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Tested on x86_64-pc-linux-gnu, does this look OK for trunk and backports? -- >8 -- Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2 Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Tested on x86_64-pc-linux-gnu, does this look OK for trunk and backports? -- >8 -- Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2 Subject: [PATCH] libstdc++: Implement LWG 4440 feature-test macros added to <iosfwd> Tested on x86_64-pc-linux-gnu, does this look OK for trunk and backports? -- >8 -- Note __cpp_lib_char8_t doesn't use the <bits/version.h> mechanism, it's defined in c++config and thus provided by all headers by default. libstdc++-v3/ChangeLog: * include/std/iosfwd: Provide feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf. * testsuite/27_io/headers/iosfwd/synopsis.cc: Verify values of these FTMs. --- libstdc++-v3/include/std/iosfwd | 4 ++++ .../testsuite/27_io/headers/iosfwd/synopsis.cc | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd index 1d5e684b53bb..511b2f3a23f1 100644 --- a/libstdc++-v3/include/std/iosfwd +++ b/libstdc++-v3/include/std/iosfwd @@ -39,6 +39,10 @@ #include <bits/requires_hosted.h> // iostreams +#define __glibcxx_want_spanstream +#define __glibcxx_want_syncbuf +#include <bits/version.h> + /** * @defgroup io I/O * diff --git a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc index 8d9501f42ef4..81b158b81285 100644 --- a/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc +++ b/libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc @@ -3,6 +3,18 @@ #include <iosfwd> +#if __cplusplus >= 202002L && __cpp_lib_char8_t != 201907L +# error "Feature-test macro __cpp_lib_char8_t has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202202L && __cpp_lib_spanstream != 202106L +# error "Feature-test macro __cpp_lib_spanstrean has wrong value in <iosfwd>" +#endif + +#if __cplusplus >= 202002L && __cpp_lib_syncbuf != 201803L +# error "Feature-test macro __cpp_lib_syncbuf has wrong value in <iosfwd>" +#endif + namespace std { // [iosfwd.syn] -- 2.55.0.481.ga97fcc37c2