diff options
Diffstat (limited to 'lib/c++defs.h')
| -rw-r--r-- | lib/c++defs.h | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/lib/c++defs.h b/lib/c++defs.h new file mode 100644 index 0000000..8ad4695 --- /dev/null +++ b/lib/c++defs.h @@ -0,0 +1,331 @@ +/* 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 */ |