| /* C++ compatible function declaration macros. |
| Copyright (C) 2010-2019 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 <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 */ |