mingw/glib2/glib/gconstructor.h

/*
  If G_HAS_CONSTRUCTORS is true then the compiler support *both* constructors and
  destructors, in a usable way, including e.g. on library unload. If not you're on
  your own.

  Some compilers need #pragma to handle this, which does not work with macros,
  so the way you need to use this is (for constructors):

  #ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
  #pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(my_constructor)
  #endif
  G_DEFINE_CONSTRUCTOR(my_constructor)
  static void my_constructor(void) {
   ...
  }

*/

#ifndef __GTK_DOC_IGNORE__

#if  __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)

#define G_HAS_CONSTRUCTORS 1

#define G_DEFINE_CONSTRUCTOR(_func) static void __attribute__((constructor)) _func (void);
#define G_DEFINE_DESTRUCTOR(_func) static void __attribute__((destructor)) _func (void);

#elif defined (_MSC_VER) && (_MSC_VER >= 1500)
/* Visual studio 2008 and later has _Pragma */

#include <stdlib.h>

#define G_HAS_CONSTRUCTORS 1

/* We do some weird things to avoid the constructors being optimized
 * away on VS2015 if WholeProgramOptimization is enabled. First we
 * make a reference to the array from the wrapper to make sure its
 * references. Then we use a pragma to make sure the wrapper function
 * symbol is always included at the link stage. Also, the symbols
 * need to be extern (but not dllexport), even though they are not
 * really used from another object file.
 */

/* We need to account for differences between the mangling of symbols
 * for x86 and x64/ARM/ARM64 programs, as symbols on x86 are prefixed
 * with an underscore but symbols on x64/ARM/ARM64 are not.
 */
#ifdef _M_IX86
#define G_MSVC_SYMBOL_PREFIX "_"
#else
#define G_MSVC_SYMBOL_PREFIX ""
#endif

#define G_DEFINE_CONSTRUCTOR(_func) G_MSVC_CTOR (_func, G_MSVC_SYMBOL_PREFIX)
#define G_DEFINE_DESTRUCTOR(_func) G_MSVC_DTOR (_func, G_MSVC_SYMBOL_PREFIX)

#define G_MSVC_CTOR(_func,_sym_prefix) \
  static void _func(void); \
  extern int (* _array ## _func)(void);              \
  int _func ## _wrapper(void) { _func(); g_slist_find (NULL,  _array ## _func); return 0; } \
  __pragma(comment(linker,"/include:" _sym_prefix # _func "_wrapper")) \
  __pragma(section(".CRT$XCU",read)) \
  __declspec(allocate(".CRT$XCU")) int (* _array ## _func)(void) = _func ## _wrapper;

#define G_MSVC_DTOR(_func,_sym_prefix) \
  static void _func(void); \
  extern int (* _array ## _func)(void);              \
  int _func ## _constructor(void) { atexit (_func); g_slist_find (NULL,  _array ## _func); return 0; } \
   __pragma(comment(linker,"/include:" _sym_prefix # _func "_constructor")) \
  __pragma(section(".CRT$XCU",read)) \
  __declspec(allocate(".CRT$XCU")) int (* _array ## _func)(void) = _func ## _constructor;

#elif defined (_MSC_VER)

#define G_HAS_CONSTRUCTORS 1

/* Pre Visual studio 2008 must use #pragma section */
#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1

#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
  section(".CRT$XCU",read)
#define G_DEFINE_CONSTRUCTOR(_func) \
  static void _func(void); \
  static int _func ## _wrapper(void) { _func(); return 0; } \
  __declspec(allocate(".CRT$XCU")) static int (*p)(void) = _func ## _wrapper;

#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
  section(".CRT$XCU",read)
#define G_DEFINE_DESTRUCTOR(_func) \
  static void _func(void); \
  static int _func ## _constructor(void) { atexit (_func); return 0; } \
  __declspec(allocate(".CRT$XCU")) static int (* _array ## _func)(void) = _func ## _constructor;

#elif defined(__SUNPRO_C)

/* This is not tested, but i believe it should work, based on:
 * http://opensource.apple.com/source/OpenSSL098/OpenSSL098-35/src/fips/fips_premain.c
 */

#define G_HAS_CONSTRUCTORS 1

#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1

#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
  init(_func)
#define G_DEFINE_CONSTRUCTOR(_func) \
  static void _func(void);

#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
  fini(_func)
#define G_DEFINE_DESTRUCTOR(_func) \
  static void _func(void);

#else

/* constructors not supported for this compiler */

#endif

#endif /* __GTK_DOC_IGNORE__ */