diff options
Diffstat (limited to 'build-aux/snippet/c++defs.h')
| -rw-r--r-- | build-aux/snippet/c++defs.h | 89 |
1 files changed, 67 insertions, 22 deletions
diff --git a/build-aux/snippet/c++defs.h b/build-aux/snippet/c++defs.h index 585b38ab..2b819da5 100644 --- a/build-aux/snippet/c++defs.h +++ b/build-aux/snippet/c++defs.h @@ -1,5 +1,5 @@ /* C++ compatible function declaration macros. - Copyright (C) 2010-2015 Free Software Foundation, Inc. + 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 @@ -17,6 +17,15 @@ #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 @@ -111,14 +120,25 @@ 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 \ { \ - rettype (*const func) parameters = ::rpl_func; \ + 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 @@ -135,8 +155,15 @@ # define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \ namespace GNULIB_NAMESPACE \ { \ - rettype (*const func) parameters = \ - reinterpret_cast<rettype(*)parameters>(::rpl_func); \ + 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 @@ -150,19 +177,24 @@ 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 - /* If we were to write - rettype (*const func) parameters = ::func; - like above in _GL_CXXALIAS_RPL_1, the compiler could optimize calls - better (remove an indirection through a 'static' pointer variable), - but then the _GL_CXXALIASWARN macro below would cause a warning not only - for uses of ::func but also for uses of GNULIB_NAMESPACE::func. */ -# define _GL_CXXALIAS_SYS(func,rettype,parameters) \ - namespace GNULIB_NAMESPACE \ - { \ - static rettype (*func) parameters = ::func; \ - } \ +# 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) \ @@ -178,8 +210,15 @@ # define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \ namespace GNULIB_NAMESPACE \ { \ - static rettype (*func) parameters = \ - reinterpret_cast<rettype(*)parameters>(::func); \ + 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 @@ -202,9 +241,15 @@ # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \ namespace GNULIB_NAMESPACE \ { \ - static rettype (*func) parameters = \ - reinterpret_cast<rettype(*)parameters>( \ - (rettype2(*)parameters2)(::func)); \ + 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 |