Like for the other *.in.h files, it makes sense to add a unit test
for this .h file. Done through the second patch below.
It uncovers a compilation error:
g++ -ftrapv -DHAVE_CONFIG_H -I. -I../../gltests -I..
-DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I../../gltests -I..
-I../../gltests/.. -I../gllib -I../../gltests/../gllib
-I/media/develdata/devel/inst-x86_64-64/include -Wall -Wno-error -O0
-fno-omit-frame-pointer -ggdb -MT test-stdbit-h-c++.o -MD -MP -MF
.deps/test-stdbit-h-c++.Tpo -c -o test-stdbit-h-c++.o
../../gltests/test-stdbit-h-c++.cc
In file included from /usr/include/c++/11/bits/stringfwd.h:40,
from /usr/include/c++/11/iosfwd:39,
from /usr/include/c++/11/ios:38,
from /usr/include/c++/11/ostream:38,
from /usr/include/c++/11/iostream:39,
from ../../gltests/test-stdbit-h-c++.cc:26:
/usr/include/c++/11/bits/memoryfwd.h:63:3: error: template with C linkage
63 | template<typename>
| ^~~~~~~~
In file included from ../../gltests/test-stdbit-h-c++.cc:22:
../gllib/stdbit.h:78:1: note: ‘extern "C"’ linkage started here
78 | extern "C" {
| ^~~~~~~~~~
In file included from /usr/include/c++/11/bits/stringfwd.h:40,
from /usr/include/c++/11/iosfwd:39,
from /usr/include/c++/11/ios:38,
from /usr/include/c++/11/ostream:38,
from /usr/include/c++/11/iostream:39,
from ../../gltests/test-stdbit-h-c++.cc:26:
...
The first patch below fixes it.
2024-05-15 Bruno Haible <br...@clisp.org>
stdbit-h: Add tests.
* tests/test-stdbit-h.c: New file.
* tests/test-stdbit-h-c++.cc: New file.
* modules/stdbit-h-tests: New file.
* modules/stdbit-h-c++-tests: New file.
2024-05-15 Bruno Haible <br...@clisp.org>
stdbit-h: Make it work in C++ mode.
* lib/stdbit.in.h: Remove extraneous 'extern "C" {' marker.
>From 182c7eb43345f26178f9a3f794c85e684e96c370 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Thu, 16 May 2024 01:20:08 +0200
Subject: [PATCH 1/2] stdbit-h: Make it work in C++ mode.
* lib/stdbit.in.h: Remove extraneous 'extern "C" {' marker.
---
ChangeLog | 5 +++++
lib/stdbit.in.h | 4 ----
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 377dbe99bb..9ce6d303c6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2024-05-15 Bruno Haible <br...@clisp.org>
+
+ stdbit-h: Make it work in C++ mode.
+ * lib/stdbit.in.h: Remove extraneous 'extern "C" {' marker.
+
2024-05-15 Bruno Haible <br...@clisp.org>
stdbit-h, stdc_*: New modules, part of the stdbit module.
diff --git a/lib/stdbit.in.h b/lib/stdbit.in.h
index 73b234791d..f241a5c573 100644
--- a/lib/stdbit.in.h
+++ b/lib/stdbit.in.h
@@ -73,10 +73,6 @@ _GL_INLINE_HEADER_BEGIN
# define _GL_STDC_BIT_CEIL_INLINE _GL_INLINE
#endif
-#ifdef __cplusplus
-extern "C" {
-#endif
-
/* An expression, preferably with the type of A, that has the value of B. */
#if ((defined __GNUC__ && 2 <= __GNUC__) \
|| (defined __clang_major__ && 4 <= __clang_major__) \
--
2.34.1
>From 1a016b72a9ea5d48c6eab35494282ec657db6e18 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Thu, 16 May 2024 01:23:39 +0200
Subject: [PATCH 2/2] stdbit-h: Add tests.
* tests/test-stdbit-h.c: New file.
* tests/test-stdbit-h-c++.cc: New file.
* modules/stdbit-h-tests: New file.
* modules/stdbit-h-c++-tests: New file.
---
ChangeLog | 8 ++++++++
modules/stdbit-h-c++-tests | 17 ++++++++++++++++
modules/stdbit-h-tests | 12 ++++++++++++
tests/test-stdbit-h-c++.cc | 32 ++++++++++++++++++++++++++++++
tests/test-stdbit-h.c | 40 ++++++++++++++++++++++++++++++++++++++
5 files changed, 109 insertions(+)
create mode 100644 modules/stdbit-h-c++-tests
create mode 100644 modules/stdbit-h-tests
create mode 100644 tests/test-stdbit-h-c++.cc
create mode 100644 tests/test-stdbit-h.c
diff --git a/ChangeLog b/ChangeLog
index 9ce6d303c6..9a69d7e2aa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2024-05-15 Bruno Haible <br...@clisp.org>
+
+ stdbit-h: Add tests.
+ * tests/test-stdbit-h.c: New file.
+ * tests/test-stdbit-h-c++.cc: New file.
+ * modules/stdbit-h-tests: New file.
+ * modules/stdbit-h-c++-tests: New file.
+
2024-05-15 Bruno Haible <br...@clisp.org>
stdbit-h: Make it work in C++ mode.
diff --git a/modules/stdbit-h-c++-tests b/modules/stdbit-h-c++-tests
new file mode 100644
index 0000000000..aad80e4f8d
--- /dev/null
+++ b/modules/stdbit-h-c++-tests
@@ -0,0 +1,17 @@
+Files:
+tests/test-stdbit-h-c++.cc
+
+Status:
+c++-test
+
+Depends-on:
+ansi-c++-opt
+
+configure.ac:
+
+Makefile.am:
+if ANSICXX
+TESTS += test-stdbit-h-c++
+check_PROGRAMS += test-stdbit-h-c++
+test_stdbit_h_c___SOURCES = test-stdbit-h-c++.cc
+endif
diff --git a/modules/stdbit-h-tests b/modules/stdbit-h-tests
new file mode 100644
index 0000000000..67a8ff645c
--- /dev/null
+++ b/modules/stdbit-h-tests
@@ -0,0 +1,12 @@
+Files:
+tests/test-stdbit-h.c
+tests/macros.h
+
+Depends-on:
+stdbit-h-c++-tests
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-stdbit-h
+check_PROGRAMS += test-stdbit-h
diff --git a/tests/test-stdbit-h-c++.cc b/tests/test-stdbit-h-c++.cc
new file mode 100644
index 0000000000..db19ea798d
--- /dev/null
+++ b/tests/test-stdbit-h-c++.cc
@@ -0,0 +1,32 @@
+/* Test of <stdbit.h> substitute in C++ mode.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <br...@clisp.org>, 2024. */
+
+#define GNULIB_NAMESPACE gnulib
+#include <config.h>
+
+#include <stdbit.h>
+
+/* Check against conflicts between <stdbit.h> and the C++ header files. */
+#include <stddef.h>
+#include <iostream>
+
+
+int
+main ()
+{
+}
diff --git a/tests/test-stdbit-h.c b/tests/test-stdbit-h.c
new file mode 100644
index 0000000000..f024e4ac6f
--- /dev/null
+++ b/tests/test-stdbit-h.c
@@ -0,0 +1,40 @@
+/* Test of <stdbit.h> substitute.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <br...@clisp.org>, 2024. */
+
+#include <config.h>
+
+#include <stdbit.h>
+
+/* Check that __STDC_ENDIAN_BIG__ and __STDC_ENDIAN_LITTLE__ are defined. */
+int a[2] = { __STDC_ENDIAN_BIG__, __STDC_ENDIAN_LITTLE__ };
+
+/* Check that __STDC_ENDIAN_NATIVE__ is defined. */
+int b = __STDC_ENDIAN_NATIVE__;
+
+/* Check that __STDC_ENDIAN_NATIVE__ is either __STDC_ENDIAN_BIG__ or
+ __STDC_ENDIAN_LITTLE__. */
+#if !(__STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_BIG__ \
+ || __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_LITTLE__)
+# error "unknown endianness"
+#endif
+
+int
+main (void)
+{
+ return 0;
+}
--
2.34.1
