#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(::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(::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((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 , 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 , 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 */