diff options
| author | Paul Eggert <eggert@cs.ucla.edu> | 2023-02-09 17:09:23 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2023-02-09 17:10:04 -0800 |
| commit | 36f06b07d9cfb3974c160ecc22def3cb1b117106 (patch) | |
| tree | eba82ebe3f3873938c6183075ec26758fb7bf180 | |
| parent | 8eb1529674c157efe5ed902d361c8c779116d4a1 (diff) | |
| download | gnulib-36f06b07d9cfb3974c160ecc22def3cb1b117106.tar.gz | |
nullptr: work around Apple clang 14 issue
Problem reported by Bruno Haible in:
https://lists.gnu.org/r/bug-gnulib/2023-02/msg00098.html
* doc/gnulib.texi (nullptr): Document limitations better.
* m4/nullptr.m4 (gl_NULLPTR): Check for incompatibility of macOS
clang 14.0.0 (clang-1400.0.29.202), where <stddef.h> defines a
non-working nullptr macro.
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | doc/gnulib.texi | 7 | ||||
| -rw-r--r-- | m4/nullptr.m4 | 30 |
3 files changed, 34 insertions, 13 deletions
@@ -1,3 +1,13 @@ +2023-02-09 Paul Eggert <eggert@cs.ucla.edu> + + nullptr: work around Apple clang 14 issue + Problem reported by Bruno Haible in: + https://lists.gnu.org/r/bug-gnulib/2023-02/msg00098.html + * doc/gnulib.texi (nullptr): Document limitations better. + * m4/nullptr.m4 (gl_NULLPTR): Check for incompatibility of macOS + clang 14.0.0 (clang-1400.0.29.202), where <stddef.h> defines a + non-working nullptr macro. + 2023-02-09 Bruno Haible <bruno@clisp.org> math: Fix compilation error in C++ mode on macOS 12.5. diff --git a/doc/gnulib.texi b/doc/gnulib.texi index 6fe2678834..28d8c20d8c 100644 --- a/doc/gnulib.texi +++ b/doc/gnulib.texi @@ -954,9 +954,10 @@ In C, it has type @code{void *}; in C++ it has an integer type. @item On older platforms Gnulib cannot easily emulate @code{nullptr_t}, so -null pointer type checking is more error prone, and @code{_Generic} -expressions cannot reliably distinguish @code{nullptr}'s type from -integer or @code{void *} types. +null pointer type checking is more error prone. In C, @code{_Generic} +expressions cannot reliably distinguish the type of @code{nullptr} +from integer or @code{void *} types. C++ overloading has similar +limitations. @end itemize @node static_assert diff --git a/m4/nullptr.m4 b/m4/nullptr.m4 index a0b438be94..1f8ab51b85 100644 --- a/m4/nullptr.m4 +++ b/m4/nullptr.m4 @@ -28,20 +28,30 @@ AC_DEFUN([gl_NULLPTR], [AC_COMPILE_IFELSE( [AC_LANG_SOURCE([[int *p = nullptr;]])], [gl_cv_cxx_nullptr=yes], - [gl_cv_cxx_nullptr=no])]) - gl_cxx_nullptr=$gl_cv_cxx_nullptr - AC_LANG_POP([C++])], - [gl_cxx_nullptr=no]) - if test "$gl_cxx_nullptr" = yes; then - AC_DEFINE([HAVE_CXX_NULLPTR], [1], [Define to 1 if C++ nullptr works.]) - fi + [AC_COMPILE_IFELSE( + [AC_LANG_SOURCE([[#include <stddef.h> + int *p = nullptr;]])], + [gl_cv_cxx_nullptr="yes, but it is a <stddef.h> macro"], + [gl_cv_cxx_nullptr=no])])]) + AS_CASE([$gl_cv_cxx_nullptr], + [yes], [gl_have_cxx_nullptr=1], + [yes*], [gl_have_cxx_nullptr="(-1)"], + [gl_have_cxx_nullptr=0]) + AC_DEFINE_UNQUOTED([HAVE_CXX_NULLPTR], [$gl_have_cxx_nullptr], + [Define to 1 if C++ nullptr works, 0 if not, + (-1) if it is a <stddef.h> macro.]) + AC_LANG_POP([C++])]) ]) - AH_VERBATIM([nullptr], -[#ifndef nullptr /* keep config.h idempotent */ + AH_VERBATIM([zznullptr], +[#if defined __cplusplus && HAVE_CXX_NULLPTR < 0 +# include <stddef.h> +# undef/**/nullptr +#endif +#ifndef nullptr # if !defined __cplusplus && !defined HAVE_C_NULLPTR # define nullptr ((void *) 0) -# elif defined __cplusplus && !defined HAVE_CXX_NULLPTR +# elif defined __cplusplus && HAVE_CXX_NULLPTR <= 0 # if 3 <= __GNUG__ # define nullptr __null # else |