include/ruby/internal/dllexport.h

   1 #ifndef RBIMPL_DLLEXPORT_H                           /*-*-C++-*-vi:se ft=cpp:*/
   2 #define RBIMPL_DLLEXPORT_H
   3 /**
   4  * @file
   5  * @author     Ruby developers <ruby-core@ruby-lang.org>
   6  * @copyright  This  file  is   a  part  of  the   programming  language  Ruby.
   7  *             Permission  is hereby  granted,  to  either redistribute  and/or
   8  *             modify this file, provided that  the conditions mentioned in the
   9  *             file COPYING are met.  Consult the file for details.
  10  * @warning    Symbols   prefixed  with   either  `RBIMPL`   or  `rbimpl`   are
  11  *             implementation details.   Don't take  them as canon.  They could
  12  *             rapidly appear then vanish.  The name (path) of this header file
  13  *             is also an  implementation detail.  Do not expect  it to persist
  14  *             at the place it is now.  Developers are free to move it anywhere
  15  *             anytime at will.
  16  * @note       To  ruby-core:  remember  that   this  header  can  be  possibly
  17  *             recursively included  from extension  libraries written  in C++.
  18  *             Do not  expect for  instance `__VA_ARGS__` is  always available.
  19  *             We assume C99  for ruby itself but we don't  assume languages of
  20  *             extension libraries.  They could be written in C++98.
  21  * @brief      Tweaking visibility of C variables/functions.
  22  */
  23 #include "ruby/internal/config.h"
  24 #include "ruby/internal/compiler_is.h"
  25
  26 /**
  27  * Declaration of externally visible global variables.  Here "externally" means
  28  * they should  be visible  from extension  libraries.  Depending  on operating
  29  * systems (dynamic linkers,  to be precise), global variables inside  of a DLL
  30  * may  or may  not be  visible  form outside  of  that DLL  by default.   This
  31  * declaration manually tweaks  that default and ensures  the declared variable
  32  * be truly globally visible.
  33  *
  34  * ```CXX
  35  * extern VALUE foo;      // hidden on some OS
  36  * RUBY_EXTERN VALUE foo; // ensure visible
  37  * ```
  38  */
  39 #undef RUBY_EXTERN
  40 #if defined(MJIT_HEADER) && defined(_WIN32)
  41 # define RUBY_EXTERN extern __declspec(dllimport)
  42 #elif defined(RUBY_EXPORT)
  43 # define RUBY_EXTERN extern
  44 #elif defined(_WIN32)
  45 # define RUBY_EXTERN extern __declspec(dllimport)
  46 #else
  47 # define RUBY_EXTERN extern
  48 #endif
  49
  50 #ifndef RUBY_SYMBOL_EXPORT_BEGIN
  51 # define RUBY_SYMBOL_EXPORT_BEGIN /* begin */
  52 #endif
  53
  54 #ifndef RUBY_SYMBOL_EXPORT_END
  55 # define RUBY_SYMBOL_EXPORT_END   /* end */
  56 #endif
  57
  58 #ifndef RUBY_FUNC_EXPORTED
  59 # define RUBY_FUNC_EXPORTED /* void */
  60 #endif
  61
  62 /**
  63  * @cond INTERNAL_MACRO
  64  *
  65  * These MJIT related macros are placed here because translate_mjit_header can
  66  * need them.  Extension libraries should not touch.
  67  */
  68
  69 /* These macros are used for functions which are exported only for MJIT
  70    and NOT ensured to be exported in future versions. */
  71
  72 /* On mswin, MJIT header transformation can't be used since cl.exe can't output
  73    preprocessed output preserving macros. So this `MJIT_STATIC` is needed
  74    to force non-static function to static on MJIT header to avoid symbol conflict. */
  75 #ifdef MJIT_HEADER
  76 # define MJIT_STATIC static
  77 #else
  78 # define MJIT_STATIC
  79 #endif
  80
  81 /** @endcond */
  82
  83 /** Shortcut macro equivalent to `RUBY_SYMBOL_EXPORT_BEGIN extern "C" {`.
  84  * \@shyouhei finds it handy. */
  85 #if defined(__DOXYGEN__)
  86 # define RBIMPL_SYMBOL_EXPORT_BEGIN() /* void */
  87 #elif defined(__cplusplus)
  88 # define RBIMPL_SYMBOL_EXPORT_BEGIN() RUBY_SYMBOL_EXPORT_BEGIN extern "C" {
  89 #else
  90 # define RBIMPL_SYMBOL_EXPORT_BEGIN() RUBY_SYMBOL_EXPORT_BEGIN
  91 #endif
  92
  93 /** Counterpart of #RBIMPL_SYMBOL_EXPORT_BEGIN */
  94 #if defined(__DOXYGEN__)
  95 # define RBIMPL_SYMBOL_EXPORT_END() /* void */
  96 #elif defined(__cplusplus)
  97 # define RBIMPL_SYMBOL_EXPORT_END() } RUBY_SYMBOL_EXPORT_END
  98 #else
  99 # define RBIMPL_SYMBOL_EXPORT_END()   RUBY_SYMBOL_EXPORT_END
 100 #endif
 101 #endif /* RBIMPL_DLLEXPORT_H */