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+/* C++ compatible function declaration macros.
+ Copyright (C) 2010-2023 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 2 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+#ifndef _GL_CXXDEFS_H
+#define _GL_CXXDEFS_H
+
+/* Begin/end the GNULIB_NAMESPACE namespace. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_BEGIN_NAMESPACE namespace GNULIB_NAMESPACE {
+# define _GL_END_NAMESPACE }
+#else
+# define _GL_BEGIN_NAMESPACE
+# define _GL_END_NAMESPACE
+#endif
+
+/* The three most frequent use cases of these macros are:
+
+ * For providing a substitute for a function that is missing on some
+ platforms, but is declared and works fine on the platforms on which
+ it exists:
+
+ #if @GNULIB_FOO@
+ # if !@HAVE_FOO@
+ _GL_FUNCDECL_SYS (foo, ...);
+ # endif
+ _GL_CXXALIAS_SYS (foo, ...);
+ _GL_CXXALIASWARN (foo);
+ #elif defined GNULIB_POSIXCHECK
+ ...
+ #endif
+
+ * For providing a replacement for a function that exists on all platforms,
+ but is broken/insufficient and needs to be replaced on some platforms:
+
+ #if @GNULIB_FOO@
+ # if @REPLACE_FOO@
+ # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+ # undef foo
+ # define foo rpl_foo
+ # endif
+ _GL_FUNCDECL_RPL (foo, ...);
+ _GL_CXXALIAS_RPL (foo, ...);
+ # else
+ _GL_CXXALIAS_SYS (foo, ...);
+ # endif
+ _GL_CXXALIASWARN (foo);
+ #elif defined GNULIB_POSIXCHECK
+ ...
+ #endif
+
+ * For providing a replacement for a function that exists on some platforms
+ but is broken/insufficient and needs to be replaced on some of them and
+ is additionally either missing or undeclared on some other platforms:
+
+ #if @GNULIB_FOO@
+ # if @REPLACE_FOO@
+ # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+ # undef foo
+ # define foo rpl_foo
+ # endif
+ _GL_FUNCDECL_RPL (foo, ...);
+ _GL_CXXALIAS_RPL (foo, ...);
+ # else
+ # if !@HAVE_FOO@ or if !@HAVE_DECL_FOO@
+ _GL_FUNCDECL_SYS (foo, ...);
+ # endif
+ _GL_CXXALIAS_SYS (foo, ...);
+ # endif
+ _GL_CXXALIASWARN (foo);
+ #elif defined GNULIB_POSIXCHECK
+ ...
+ #endif
+*/
+
+/* _GL_EXTERN_C declaration;
+ performs the declaration with C linkage. */
+#if defined __cplusplus
+# define _GL_EXTERN_C extern "C"
+#else
+# define _GL_EXTERN_C extern
+#endif
+
+/* _GL_FUNCDECL_RPL (func, rettype, parameters_and_attributes);
+ declares a replacement function, named rpl_func, with the given prototype,
+ consisting of return type, parameters, and attributes.
+ Example:
+ _GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
+ _GL_ARG_NONNULL ((1)));
+ */
+#define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
+ _GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
+#define _GL_FUNCDECL_RPL_1(rpl_func,rettype,parameters_and_attributes) \
+ _GL_EXTERN_C rettype rpl_func parameters_and_attributes
+
+/* _GL_FUNCDECL_SYS (func, rettype, parameters_and_attributes);
+ declares the system function, named func, with the given prototype,
+ consisting of return type, parameters, and attributes.
+ Example:
+ _GL_FUNCDECL_SYS (open, int, (const char *filename, int flags, ...)
+ _GL_ARG_NONNULL ((1)));
+ */
+#define _GL_FUNCDECL_SYS(func,rettype,parameters_and_attributes) \
+ _GL_EXTERN_C rettype func parameters_and_attributes
+
+/* _GL_CXXALIAS_RPL (func, rettype, parameters);
+ declares a C++ alias called GNULIB_NAMESPACE::func
+ that redirects to rpl_func, if GNULIB_NAMESPACE is defined.
+ Example:
+ _GL_CXXALIAS_RPL (open, int, (const char *filename, int flags, ...));
+
+ Wrapping rpl_func in an object with an inline conversion operator
+ avoids a reference to rpl_func unless GNULIB_NAMESPACE::func is
+ actually used in the program. */
+#define _GL_CXXALIAS_RPL(func,rettype,parameters) \
+ _GL_CXXALIAS_RPL_1 (func, rpl_##func, rettype, parameters)
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
+ namespace GNULIB_NAMESPACE \
+ { \
+ static const struct _gl_ ## func ## _wrapper \
+ { \
+ typedef rettype (*type) parameters; \
+ \
+ inline operator type () const \
+ { \
+ return ::rpl_func; \
+ } \
+ } func = {}; \
+ } \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#else
+# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIAS_MDA (func, rettype, parameters);
+ is to be used when func is a Microsoft deprecated alias, on native Windows.
+ It declares a C++ alias called GNULIB_NAMESPACE::func
+ that redirects to _func, if GNULIB_NAMESPACE is defined.
+ Example:
+ _GL_CXXALIAS_MDA (open, int, (const char *filename, int flags, ...));
+ */
+#define _GL_CXXALIAS_MDA(func,rettype,parameters) \
+ _GL_CXXALIAS_RPL_1 (func, _##func, rettype, parameters)
+
+/* _GL_CXXALIAS_RPL_CAST_1 (func, rpl_func, rettype, parameters);
+ is like _GL_CXXALIAS_RPL_1 (func, rpl_func, rettype, parameters);
+ except that the C function rpl_func may have a slightly different
+ declaration. A cast is used to silence the "invalid conversion" error
+ that would otherwise occur. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
+ namespace GNULIB_NAMESPACE \
+ { \
+ static const struct _gl_ ## func ## _wrapper \
+ { \
+ typedef rettype (*type) parameters; \
+ \
+ inline operator type () const \
+ { \
+ return reinterpret_cast<type>(::rpl_func); \
+ } \
+ } func = {}; \
+ } \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#else
+# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIAS_MDA_CAST (func, rettype, parameters);
+ is like _GL_CXXALIAS_MDA (func, rettype, parameters);
+ except that the C function func may have a slightly different declaration.
+ A cast is used to silence the "invalid conversion" error that would
+ otherwise occur. */
+#define _GL_CXXALIAS_MDA_CAST(func,rettype,parameters) \
+ _GL_CXXALIAS_RPL_CAST_1 (func, _##func, rettype, parameters)
+
+/* _GL_CXXALIAS_SYS (func, rettype, parameters);
+ declares a C++ alias called GNULIB_NAMESPACE::func
+ that redirects to the system provided function func, if GNULIB_NAMESPACE
+ is defined.
+ Example:
+ _GL_CXXALIAS_SYS (open, int, (const char *filename, int flags, ...));
+
+ Wrapping func in an object with an inline conversion operator
+ avoids a reference to func unless GNULIB_NAMESPACE::func is
+ actually used in the program. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
+ namespace GNULIB_NAMESPACE \
+ { \
+ static const struct _gl_ ## func ## _wrapper \
+ { \
+ typedef rettype (*type) parameters; \
+ \
+ inline operator type () const \
+ { \
+ return ::func; \
+ } \
+ } func = {}; \
+ } \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#else
+# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIAS_SYS_CAST (func, rettype, parameters);
+ is like _GL_CXXALIAS_SYS (func, rettype, parameters);
+ except that the C function func may have a slightly different declaration.
+ A cast is used to silence the "invalid conversion" error that would
+ otherwise occur. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
+ namespace GNULIB_NAMESPACE \
+ { \
+ static const struct _gl_ ## func ## _wrapper \
+ { \
+ typedef rettype (*type) parameters; \
+ \
+ inline operator type () const \
+ { \
+ return reinterpret_cast<type>(::func); \
+ } \
+ } func = {}; \
+ } \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#else
+# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIAS_SYS_CAST2 (func, rettype, parameters, rettype2, parameters2);
+ is like _GL_CXXALIAS_SYS (func, rettype, parameters);
+ except that the C function is picked among a set of overloaded functions,
+ namely the one with rettype2 and parameters2. Two consecutive casts
+ are used to silence the "cannot find a match" and "invalid conversion"
+ errors that would otherwise occur. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+ /* The outer cast must be a reinterpret_cast.
+ The inner cast: When the function is defined as a set of overloaded
+ functions, it works as a static_cast<>, choosing the designated variant.
+ When the function is defined as a single variant, it works as a
+ reinterpret_cast<>. The parenthesized cast syntax works both ways. */
+# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
+ namespace GNULIB_NAMESPACE \
+ { \
+ static const struct _gl_ ## func ## _wrapper \
+ { \
+ typedef rettype (*type) parameters; \
+ \
+ inline operator type () const \
+ { \
+ return reinterpret_cast<type>((rettype2 (*) parameters2)(::func)); \
+ } \
+ } func = {}; \
+ } \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#else
+# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIASWARN (func);
+ causes a warning to be emitted when ::func is used but not when
+ GNULIB_NAMESPACE::func is used. func must be defined without overloaded
+ variants. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIASWARN(func) \
+ _GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
+# define _GL_CXXALIASWARN_1(func,namespace) \
+ _GL_CXXALIASWARN_2 (func, namespace)
+/* To work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
+ we enable the warning only when not optimizing. */
+# if !(defined __GNUC__ && !defined __clang__ && __OPTIMIZE__)
+# define _GL_CXXALIASWARN_2(func,namespace) \
+ _GL_WARN_ON_USE (func, \
+ "The symbol ::" #func " refers to the system function. " \
+ "Use " #namespace "::" #func " instead.")
+# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+# define _GL_CXXALIASWARN_2(func,namespace) \
+ extern __typeof__ (func) func
+# else
+# define _GL_CXXALIASWARN_2(func,namespace) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+# endif
+#else
+# define _GL_CXXALIASWARN(func) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+/* _GL_CXXALIASWARN1 (func, rettype, parameters_and_attributes);
+ causes a warning to be emitted when the given overloaded variant of ::func
+ is used but not when GNULIB_NAMESPACE::func is used. */
+#if defined __cplusplus && defined GNULIB_NAMESPACE
+# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
+ _GL_CXXALIASWARN1_1 (func, rettype, parameters_and_attributes, \
+ GNULIB_NAMESPACE)
+# define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
+ _GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
+/* To work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
+ we enable the warning only when not optimizing. */
+# if !(defined __GNUC__ && !defined __clang__ && __OPTIMIZE__)
+# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
+ _GL_WARN_ON_USE_CXX (func, rettype, rettype, parameters_and_attributes, \
+ "The symbol ::" #func " refers to the system function. " \
+ "Use " #namespace "::" #func " instead.")
+# else
+# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+# endif
+#else
+# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
+ _GL_EXTERN_C int _gl_cxxalias_dummy
+#endif
+
+#endif /* _GL_CXXDEFS_H */