[deliverable/binutils-gdb.git] / gnulib / import / extra / snippet / c++defs.h

/* C++ compatible function declaration macros.
   Copyright (C) 2010-2016 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 <http://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 type rpl () const { return ::rpl_func; }       \
        inline operator type () const  { return rpl (); }     \
      } 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_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 type rpl () const                                   \
        { return reinterpret_cast<type>(::rpl_func); }             \
        inline operator type () const { return rpl (); }           \
      } 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_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 type rpl () const { return ::func; }           \
        inline operator type () const { return rpl (); }      \
      } 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 type rpl () const                        \
        { return reinterpret_cast<type>(::func); }      \
        inline operator type () const { return rpl (); }\
      } 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 type rpl () const                                              \
        { return reinterpret_cast<type>((rettype2 (*) parameters2)(::func)); }\
                                                                              \
        inline operator type () const { return rpl (); }                      \
      } 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 <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
   we enable the warning only when not optimizing.  */
# if !__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 <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
   we enable the warning only when not optimizing.  */
# if !__OPTIMIZE__
#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
    _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
                         "The symbol ::" #func " refers to the system function. " \
                         "Use " #namespace "::" #func " instead.")
# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
     extern __typeof__ (func) func
# 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 */
Commit	Line	Data
f434ba03	1	/* C++ compatible function declaration macros.
5e8754f9	2	Copyright (C) 2010-2016 Free Software Foundation, Inc.
f434ba03 PA	3
	4	This program is free software: you can redistribute it and/or modify it
	5	under the terms of the GNU General Public License as published
	6	by the Free Software Foundation; either version 3 of the License, or
	7	(at your option) any later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
770d76d7	12	General Public License for more details.
f434ba03 PA	13
f434ba03 PA	14	You should have received a copy of the GNU General Public License
5e8754f9	15	along with this program. If not, see <http://www.gnu.org/licenses/>. */
f434ba03 PA	16
	17	#ifndef _GL_CXXDEFS_H
	18	#define _GL_CXXDEFS_H
	19
4c62b19f PA	20	/* Begin/end the GNULIB_NAMESPACE namespace. */
	21	#if defined __cplusplus && defined GNULIB_NAMESPACE
	22	# define _GL_BEGIN_NAMESPACE namespace GNULIB_NAMESPACE {
	23	# define _GL_END_NAMESPACE }
	24	#else
	25	# define _GL_BEGIN_NAMESPACE
	26	# define _GL_END_NAMESPACE
	27	#endif
	28
f434ba03 PA	29	/* The three most frequent use cases of these macros are:
	30
	31	* For providing a substitute for a function that is missing on some
	32	platforms, but is declared and works fine on the platforms on which
	33	it exists:
	34
	35	#if @GNULIB_FOO@
	36	# if !@HAVE_FOO@
	37	_GL_FUNCDECL_SYS (foo, ...);
	38	# endif
	39	_GL_CXXALIAS_SYS (foo, ...);
	40	_GL_CXXALIASWARN (foo);
	41	#elif defined GNULIB_POSIXCHECK
	42	...
	43	#endif
	44
	45	* For providing a replacement for a function that exists on all platforms,
	46	but is broken/insufficient and needs to be replaced on some platforms:
	47
	48	#if @GNULIB_FOO@
	49	# if @REPLACE_FOO@
	50	# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
	51	# undef foo
	52	# define foo rpl_foo
	53	# endif
	54	_GL_FUNCDECL_RPL (foo, ...);
	55	_GL_CXXALIAS_RPL (foo, ...);
	56	# else
	57	_GL_CXXALIAS_SYS (foo, ...);
	58	# endif
	59	_GL_CXXALIASWARN (foo);
	60	#elif defined GNULIB_POSIXCHECK
	61	...
	62	#endif
	63
	64	* For providing a replacement for a function that exists on some platforms
	65	but is broken/insufficient and needs to be replaced on some of them and
	66	is additionally either missing or undeclared on some other platforms:
	67
	68	#if @GNULIB_FOO@
	69	# if @REPLACE_FOO@
	70	# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
	71	# undef foo
	72	# define foo rpl_foo
	73	# endif
	74	_GL_FUNCDECL_RPL (foo, ...);
	75	_GL_CXXALIAS_RPL (foo, ...);
	76	# else
	77	# if !@HAVE_FOO@ or if !@HAVE_DECL_FOO@
	78	_GL_FUNCDECL_SYS (foo, ...);
	79	# endif
	80	_GL_CXXALIAS_SYS (foo, ...);
	81	# endif
	82	_GL_CXXALIASWARN (foo);
	83	#elif defined GNULIB_POSIXCHECK
	84	...
	85	#endif
	86	*/
	87
	88	/* _GL_EXTERN_C declaration;
	89	performs the declaration with C linkage. */
	90	#if defined __cplusplus
	91	# define _GL_EXTERN_C extern "C"
	92	#else
93	# define _GL_EXTERN_C extern
94	#endif
95
96	/* _GL_FUNCDECL_RPL (func, rettype, parameters_and_attributes);
97	declares a replacement function, named rpl_func, with the given prototype,
98	consisting of return type, parameters, and attributes.
99	Example:
100	_GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
101	_GL_ARG_NONNULL ((1)));
102	*/
103	#define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
104	_GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
105	#define _GL_FUNCDECL_RPL_1(rpl_func,rettype,parameters_and_attributes) \
106	_GL_EXTERN_C rettype rpl_func parameters_and_attributes
107
108	/* _GL_FUNCDECL_SYS (func, rettype, parameters_and_attributes);
109	declares the system function, named func, with the given prototype,
110	consisting of return type, parameters, and attributes.
111	Example:
112	_GL_FUNCDECL_SYS (open, int, (const char *filename, int flags, ...)
113	_GL_ARG_NONNULL ((1)));
114	*/
115	#define _GL_FUNCDECL_SYS(func,rettype,parameters_and_attributes) \
116	_GL_EXTERN_C rettype func parameters_and_attributes
117
118	/* _GL_CXXALIAS_RPL (func, rettype, parameters);
119	declares a C++ alias called GNULIB_NAMESPACE::func
120	that redirects to rpl_func, if GNULIB_NAMESPACE is defined.
121	Example:
122	_GL_CXXALIAS_RPL (open, int, (const char *filename, int flags, ...));
4c62b19f PA	123
	124	Wrapping rpl_func in an object with an inline conversion operator
	125	avoids a reference to rpl_func unless GNULIB_NAMESPACE::func is
	126	actually used in the program. */
f434ba03 PA	127	#define _GL_CXXALIAS_RPL(func,rettype,parameters) \
	128	_GL_CXXALIAS_RPL_1 (func, rpl_##func, rettype, parameters)
	129	#if defined __cplusplus && defined GNULIB_NAMESPACE
	130	# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
	131	namespace GNULIB_NAMESPACE \
	132	{ \
4c62b19f PA	133	static const struct _gl_ ## func ## _wrapper \
	134	{ \
	135	typedef rettype (*type) parameters; \
5e8754f9 SDJ	136	inline type rpl () const { return ::rpl_func; } \
5e8754f9 SDJ	137	inline operator type () const { return rpl (); } \
4c62b19f	138	} func = {}; \
f434ba03 PA	139	} \
	140	_GL_EXTERN_C int _gl_cxxalias_dummy
	141	#else
	142	# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
	143	_GL_EXTERN_C int _gl_cxxalias_dummy
	144	#endif
	145
	146	/* _GL_CXXALIAS_RPL_CAST_1 (func, rpl_func, rettype, parameters);
	147	is like _GL_CXXALIAS_RPL_1 (func, rpl_func, rettype, parameters);
	148	except that the C function rpl_func may have a slightly different
	149	declaration. A cast is used to silence the "invalid conversion" error
	150	that would otherwise occur. */
	151	#if defined __cplusplus && defined GNULIB_NAMESPACE
	152	# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
	153	namespace GNULIB_NAMESPACE \
	154	{ \
4c62b19f PA	155	static const struct _gl_ ## func ## _wrapper \
	156	{ \
	157	typedef rettype (*type) parameters; \
5e8754f9 SDJ	158	inline type rpl () const \
	159	{ return reinterpret_cast<type>(::rpl_func); } \
	160	inline operator type () const { return rpl (); } \
4c62b19f	161	} func = {}; \
f434ba03 PA	162	} \
	163	_GL_EXTERN_C int _gl_cxxalias_dummy
	164	#else
	165	# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
	166	_GL_EXTERN_C int _gl_cxxalias_dummy
	167	#endif
	168
	169	/* _GL_CXXALIAS_SYS (func, rettype, parameters);
	170	declares a C++ alias called GNULIB_NAMESPACE::func
	171	that redirects to the system provided function func, if GNULIB_NAMESPACE
	172	is defined.
	173	Example:
	174	_GL_CXXALIAS_SYS (open, int, (const char *filename, int flags, ...));
4c62b19f PA	175
	176	Wrapping func in an object with an inline conversion operator
	177	avoids a reference to func unless GNULIB_NAMESPACE::func is
	178	actually used in the program. */
f434ba03	179	#if defined __cplusplus && defined GNULIB_NAMESPACE
4c62b19f PA	180	# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
	181	namespace GNULIB_NAMESPACE \
	182	{ \
	183	static const struct _gl_ ## func ## _wrapper \
	184	{ \
	185	typedef rettype (*type) parameters; \
5e8754f9 SDJ	186	inline type rpl () const { return ::func; } \
5e8754f9 SDJ	187	inline operator type () const { return rpl (); } \
4c62b19f	188	} func = {}; \
5e8754f9	189	} \
f434ba03 PA	190	_GL_EXTERN_C int _gl_cxxalias_dummy
	191	#else
	192	# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
	193	_GL_EXTERN_C int _gl_cxxalias_dummy
	194	#endif
	195
	196	/* _GL_CXXALIAS_SYS_CAST (func, rettype, parameters);
	197	is like _GL_CXXALIAS_SYS (func, rettype, parameters);
	198	except that the C function func may have a slightly different declaration.
	199	A cast is used to silence the "invalid conversion" error that would
	200	otherwise occur. */
	201	#if defined __cplusplus && defined GNULIB_NAMESPACE
	202	# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
	203	namespace GNULIB_NAMESPACE \
	204	{ \
4c62b19f PA	205	static const struct _gl_ ## func ## _wrapper \
	206	{ \
	207	typedef rettype (*type) parameters; \
5e8754f9 SDJ	208	inline type rpl () const \
	209	{ return reinterpret_cast<type>(::func); } \
	210	inline operator type () const { return rpl (); }\
4c62b19f	211	} func = {}; \
f434ba03 PA	212	} \
	213	_GL_EXTERN_C int _gl_cxxalias_dummy
	214	#else
	215	# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
	216	_GL_EXTERN_C int _gl_cxxalias_dummy
	217	#endif
	218
	219	/* _GL_CXXALIAS_SYS_CAST2 (func, rettype, parameters, rettype2, parameters2);
	220	is like _GL_CXXALIAS_SYS (func, rettype, parameters);
	221	except that the C function is picked among a set of overloaded functions,
	222	namely the one with rettype2 and parameters2. Two consecutive casts
	223	are used to silence the "cannot find a match" and "invalid conversion"
	224	errors that would otherwise occur. */
	225	#if defined __cplusplus && defined GNULIB_NAMESPACE
	226	/* The outer cast must be a reinterpret_cast.
	227	The inner cast: When the function is defined as a set of overloaded
	228	functions, it works as a static_cast<>, choosing the designated variant.
	229	When the function is defined as a single variant, it works as a
	230	reinterpret_cast<>. The parenthesized cast syntax works both ways. */
	231	# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
	232	namespace GNULIB_NAMESPACE \
	233	{ \
4c62b19f PA	234	static const struct _gl_ ## func ## _wrapper \
	235	{ \
	236	typedef rettype (*type) parameters; \
	237	\
5e8754f9 SDJ	238	inline type rpl () const \
	239	{ return reinterpret_cast<type>((rettype2 (*) parameters2)(::func)); }\
	240	\
	241	inline operator type () const { return rpl (); } \
4c62b19f	242	} func = {}; \
f434ba03 PA	243	} \
	244	_GL_EXTERN_C int _gl_cxxalias_dummy
	245	#else
	246	# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
	247	_GL_EXTERN_C int _gl_cxxalias_dummy
	248	#endif
	249
	250	/* _GL_CXXALIASWARN (func);
	251	causes a warning to be emitted when ::func is used but not when
	252	GNULIB_NAMESPACE::func is used. func must be defined without overloaded
	253	variants. */
	254	#if defined __cplusplus && defined GNULIB_NAMESPACE
	255	# define _GL_CXXALIASWARN(func) \
	256	_GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
	257	# define _GL_CXXALIASWARN_1(func,namespace) \
	258	_GL_CXXALIASWARN_2 (func, namespace)
5e8754f9	259	/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
f434ba03 PA	260	we enable the warning only when not optimizing. */
	261	# if !__OPTIMIZE__
	262	# define _GL_CXXALIASWARN_2(func,namespace) \
	263	_GL_WARN_ON_USE (func, \
	264	"The symbol ::" #func " refers to the system function. " \
	265	"Use " #namespace "::" #func " instead.")
	266	# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
	267	# define _GL_CXXALIASWARN_2(func,namespace) \
	268	extern __typeof__ (func) func
	269	# else
	270	# define _GL_CXXALIASWARN_2(func,namespace) \
	271	_GL_EXTERN_C int _gl_cxxalias_dummy
	272	# endif
	273	#else
	274	# define _GL_CXXALIASWARN(func) \
	275	_GL_EXTERN_C int _gl_cxxalias_dummy
	276	#endif
	277
	278	/* _GL_CXXALIASWARN1 (func, rettype, parameters_and_attributes);
	279	causes a warning to be emitted when the given overloaded variant of ::func
	280	is used but not when GNULIB_NAMESPACE::func is used. */
	281	#if defined __cplusplus && defined GNULIB_NAMESPACE
	282	# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
	283	_GL_CXXALIASWARN1_1 (func, rettype, parameters_and_attributes, \
	284	GNULIB_NAMESPACE)
	285	# define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
	286	_GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
5e8754f9	287	/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
f434ba03 PA	288	we enable the warning only when not optimizing. */
	289	# if !__OPTIMIZE__
	290	# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
	291	_GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
	292	"The symbol ::" #func " refers to the system function. " \
	293	"Use " #namespace "::" #func " instead.")
	294	# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
	295	# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
	296	extern __typeof__ (func) func
	297	# else
	298	# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
	299	_GL_EXTERN_C int _gl_cxxalias_dummy
	300	# endif
	301	#else
	302	# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
	303	_GL_EXTERN_C int _gl_cxxalias_dummy
	304	#endif
	305
	306	#endif /* _GL_CXXDEFS_H */