/* C++ compatible function declaration macros.
Copyright (C) 2010-2018 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or
modify it under the terms of either:
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.
or both in parallel, as here.
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_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_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 !__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 !__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 */