src/include/autoinit_funcs.h

/*
 *  AutoinitFuncs: Automatic Initialization and Deinitialization Functions
 *  Copyright(C) 2014-2023 Karlson2k (Evgeny Grin)
 *
 *  This header is free software; you can redistribute it and / or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This header 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this header; if not, see
 *  <http://www.gnu.org/licenses/>.
 */

/*
   General usage is simple: include this header, declare or define two
   functions with zero parameters (void) and any return type: one for
   initialisation and one for deinitialisation, add
   _SET_INIT_AND_DEINIT_FUNCS(FuncInitName, FuncDeInitName) to the code
   and functions will be automatically called during application startup
   and shutdown.
   This is useful for libraries as libraries don't have direct access
   to main() functions.
   Example:
   -------------------------------------------------
   #include <stdlib.h>
   #include "autoinit_funcs.h"

   int someVar;
   void* somePtr;

   void libInit(void)
   {
     someVar = 3;
     somePtr = malloc(100);
   }

   void libDeinit(void)
   {
     free(somePtr);
   }

   _SET_INIT_AND_DEINIT_FUNCS(libInit,libDeinit);
   -------------------------------------------------

   If initialiser or deinitialiser function is not needed, just define
   it as empty function.

   This header should work with GCC, clang, MSVC (2010 or later) and
   SunPro / Sun Studio / Oracle Solaris Studio / Oracle Developer Studio
   compiler.
   Supported C and C++ languages; application, static and dynamic (DLL)
   libraries; non-optimized (Debug) and optimised (Release) compilation
   and linking.

   For more information see header code and comments in code.
 */
#ifndef AUTOINIT_FUNCS_INCLUDED
#define AUTOINIT_FUNCS_INCLUDED 1

/**
* Current version of the header in packed BCD form.
* 0x01093001 = 1.9.30-1.
*/
#define AUTOINIT_FUNCS_VERSION 0x01001000

#if defined(__GNUC__) || defined(__clang__)
/* if possible - check for supported attribute */
#ifdef __has_attribute
#if ! __has_attribute (constructor) || ! __has_attribute (destructor)
#define _GNUC_ATTR_CONSTR_NOT_SUPPORTED 1
#endif /* !__has_attribute(constructor) || !__has_attribute(destructor) */
#endif /* __has_attribute */
#endif /* __GNUC__ */

/* "__has_attribute__ ((constructor))" is supported by GCC, clang and
   Sun/Oracle compiler starting from version 12.1. */
#if ((defined(__GNUC__) || defined(__clang__)) && \
  ! defined(_GNUC_ATTR_CONSTR_NOT_SUPPORTED)) || \
  (defined(__SUNPRO_C) && __SUNPRO_C + 0 >= 0x5100)

#define GNUC_SET_INIT_AND_DEINIT(FI,FD) \
  void __attribute__ ((constructor)) _GNUC_init_helper_ ## FI (void);  \
  void __attribute__ ((destructor)) _GNUC_deinit_helper_ ## FD (void); \
  void __attribute__ ((constructor)) _GNUC_init_helper_ ## FI (void)   \
  { (void) (FI) (); } \
  void __attribute__ ((destructor)) _GNUC_deinit_helper_ ## FD (void)  \
  { (void) (FD) (); } \
  struct _GNUC_dummy_str_ ## FI {int i;}

#define _SET_INIT_AND_DEINIT_FUNCS(FI,FD) GNUC_SET_INIT_AND_DEINIT (FI,FD)
#define _AUTOINIT_FUNCS_ARE_SUPPORTED 1

#elif defined(_MSC_FULL_VER) && _MSC_VER + 0 >= 1600

/* Make sure that your project/sources define:
   _LIB if building a static library (_LIB is ignored if _CONSOLE is defined);
   _USRDLL if building DLL-library;
   not defined both _LIB and _USRDLL if building an application */

/* Define AUTOINIT_FUNCS_DECLARE_STATIC_REG if you need macro declaration
   for registering static initialisation functions even if you building DLL */
/* Define AUTOINIT_FUNCS_FORCE_STATIC_REG if you want to set main macro
   _SET_INIT_AND_DEINIT_FUNCS to static version even if building a DLL */

/* Stringify macros */
#define _INSTRMACRO(a) #a
#define _STRMACRO(a) _INSTRMACRO (a)

#if ! defined(_USRDLL) || defined(AUTOINIT_FUNCS_DECLARE_STATIC_REG) \
  || defined(AUTOINIT_FUNCS_FORCE_STATIC_REG)

/* Use "C" linkage for variable to simplify variable decoration */
#ifdef __cplusplus
#define W32_INITVARDECL extern "C"
#else
#define W32_INITVARDECL extern
#endif

/* How variable is decorated by compiler */
#if (defined(_WIN32) || defined(_WIN64)) \
  && ! defined(_M_IX86) && ! defined(_X86_)
#if ! defined(_M_X64) && ! defined(_M_AMD64) && ! defined(_x86_64_) \
  && ! defined(_M_ARM) && ! defined(_M_ARM64)
#pragma message(__FILE__ "(" _STRMACRO(__LINE__) ") : warning AIFW001 : " \
  "Untested architecture, linker may fail with unresolved symbol")
#endif /* ! _M_X64 && ! _M_AMD64 && ! _x86_64_ && ! _M_ARM && ! _M_ARM64 */
#define W32_VARDECORPREFIX
#define W32_DECORVARNAME(v) v
#define W32_VARDECORPREFIXSTR ""
#elif defined(_WIN32) && (defined(_M_IX86) || defined(_X86_))
#define W32_VARDECORPREFIX _
#define W32_DECORVARNAME(v) _ ## v
#define W32_VARDECORPREFIXSTR "_"
#else
#error Do not know how to decorate symbols for this architecture
#endif

/* Internal variable prefix (can be any) */
#define W32_INITHELPERVARNAME(f) _initHelperDummy_ ## f
#define W32_INITHELPERVARNAMEDECORSTR(f) \
  W32_VARDECORPREFIXSTR _STRMACRO (W32_INITHELPERVARNAME (f))

/* Declare section (segment), put variable pointing to init function to chosen segment,
   force linker to always include variable to avoid omitting by optimiser */
/* Initialisation function must be declared as
   void __cdecl FuncName(void) */
/* "extern" with initialisation value means that variable is declared AND defined. */
#define W32_VFPTR_IN_SEG(S,F) \
  __pragma (section (S,long,read)) \
  __pragma (comment (linker, "/INCLUDE:" W32_INITHELPERVARNAMEDECORSTR (F))) \
  W32_INITVARDECL __declspec(allocate (S))void \
    (__cdecl * W32_INITHELPERVARNAME (F))(void) = &F

/* Sections (segments) for pointers to initialisers/deinitialisers */

/* Semi-officially suggested section for early initialisers (called before
   C++ objects initialisers), "void" return type */
#define W32_SEG_INIT_EARLY      ".CRT$XCT"
/* Semi-officially suggested section for late initialisers (called after
   C++ objects initialisers), "void" return type */
#define W32_SEG_INIT_LATE       ".CRT$XCV"

/* Unsafe sections (segments) for pointers to initialisers/deinitialisers */

/* C++ lib initialisers, "void" return type (reserved by the system!) */
#define W32_SEG_INIT_CXX_LIB    ".CRT$XCL"
/* C++ user initialisers, "void" return type (reserved by the system!) */
#define W32_SEG_INIT_CXX_USER   ".CRT$XCU"


/* Declare section (segment), put variable pointing to init function to chosen segment,
   force linker to always include variable to avoid omitting by optimiser */
/* Initialisation function must be declared as
   int __cdecl FuncName(void) */
/* Startup process is aborted if initialiser returns non-zero */
/* "extern" with initialisation value means that variable is declared AND defined. */
#define W32_IFPTR_IN_SEG(S,F) \
  __pragma (section (S,long,read)) \
  __pragma (comment (linker, "/INCLUDE:" W32_INITHELPERVARNAMEDECORSTR (F))) \
  W32_INITVARDECL __declspec(allocate (S))int \
    (__cdecl * W32_INITHELPERVARNAME (F))(void) = &F

/* Unsafe sections (segments) for pointers to initialisers with
   "int" return type */

/* C lib initialisers, "int" return type (reserved by the system!).
   These initialisers are called before others. */
#define W32_SEG_INIT_C_LIB      ".CRT$XIL"
/* C user initialisers, "int" return type (reserved by the system!).
   These initialisers are called before others. */
#define W32_SEG_INIT_C_USER     ".CRT$XIU"


/* Declare macro for different initialisers sections */
/* Macro can be used several times to register several initialisers */
/* Once function is registered as initialiser, it will be called automatically
   during application startup */
#define W32_REG_INIT_EARLY(F) W32_VFPTR_IN_SEG (W32_SEG_INIT_EARLY,F)
#define W32_REG_INIT_LATE(F)  W32_VFPTR_IN_SEG (W32_SEG_INIT_LATE,F)


/* Not recommended / unsafe */
/* "lib" initialisers are called before "user" initialisers */
/* "C" initialisers are called before "C++" initialisers */
#define W32_REG_INIT_C_USER(F)   W32_FPTR_IN_SEG (W32_SEG_INIT_C_USER,F)
#define W32_REG_INIT_C_LIB(F)    W32_FPTR_IN_SEG (W32_SEG_INIT_C_LIB,F)
#define W32_REG_INIT_CXX_USER(F) W32_FPTR_IN_SEG (W32_SEG_INIT_CXX_USER,F)
#define W32_REG_INIT_CXX_LIB(F)  W32_FPTR_IN_SEG (W32_SEG_INIT_CXX_LIB,F)

/* Choose main register macro based on language and program type */
/* Assuming that _LIB or _USRDLL is defined for static or DLL-library */
/* Macro can be used several times to register several initialisers */
/* Once function is registered as initialiser, it will be called automatically
   during application startup */
/* Define AUTOINIT_FUNCS_FORCE_EARLY_INIT to force register as early
   initialiser */
/* Define AUTOINIT_FUNCS_FORCE_LATE_INIT to force register as late
   initialiser */
/* By default C++ static or DLL-library code and any C code and will be
   registered as early initialiser, while C++ non-library code will be
   registered as late initialiser */
#if (! defined(__cplusplus) || \
  ((defined(_LIB) && ! defined(_CONSOLE)) || defined(_USRDLL)) || \
  defined(AUTOINIT_FUNCS_FORCE_EARLY_INIT)) && \
  ! defined(AUTOINIT_FUNCS_FORCE_LATE_INIT)
#define W32_REGISTER_INIT(F) W32_REG_INIT_EARLY(F)
#else
#define W32_REGISTER_INIT(F) W32_REG_INIT_LATE(F)
#endif

#endif /* ! _USRDLL || ! AUTOINIT_FUNCS_DECLARE_STATIC_REG
          || AUTOINIT_FUNCS_FORCE_STATIC_REG */


#if ! defined(_USRDLL) || defined(AUTOINIT_FUNCS_FORCE_STATIC_REG)

#include <stdlib.h> /* required for atexit() */

#define W32_SET_INIT_AND_DEINIT(FI,FD) \
  void __cdecl _W32_init_helper_ ## FI (void);    \
  void __cdecl _W32_deinit_helper_ ## FD (void); \
  void __cdecl _W32_init_helper_ ## FI (void)     \
  { (void) (FI) (); atexit (_W32_deinit_helper_ ## FD); } \
  void __cdecl _W32_deinit_helper_ ## FD (void)  \
  { (void) (FD) (); } \
  W32_REGISTER_INIT (_W32_init_helper_ ## FI)
#else  /* _USRDLL */

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN 1
#endif /* WIN32_LEAN_AND_MEAN */

#include <Windows.h> /* Required for DllMain */

/* If DllMain is already present in code, define AUTOINIT_FUNCS_CALL_USR_DLLMAIN
   and rename DllMain to usr_DllMain */
#ifndef AUTOINIT_FUNCS_CALL_USR_DLLMAIN
#define W32_SET_INIT_AND_DEINIT(FI,FD) \
  BOOL WINAPI DllMain (HINSTANCE hinst,DWORD reason,LPVOID unused); \
  BOOL WINAPI DllMain (HINSTANCE hinst,DWORD reason,LPVOID unused)  \
  { (void) hinst; (void) unused; \
    if (DLL_PROCESS_ATTACH==reason) {(void) (FI) ();} \
    else if (DLL_PROCESS_DETACH==reason) {(void) (FD) ();} \
    return TRUE; \
  } struct _W32_dummy_strc_ ## FI {int i;}
#else  /* AUTOINIT_FUNCS_CALL_USR_DLLMAIN */
#define W32_SET_INIT_AND_DEINIT(FI,FD) \
  BOOL WINAPI usr_DllMain (HINSTANCE hinst,DWORD reason,LPVOID unused); \
  BOOL WINAPI DllMain (HINSTANCE hinst,DWORD reason,LPVOID unused); \
  BOOL WINAPI DllMain (HINSTANCE hinst,DWORD reason,LPVOID unused)  \
  { if (DLL_PROCESS_ATTACH==reason) {(void) (FI) ();} \
    else if (DLL_PROCESS_DETACH==reason) {(void) (FD) ();} \
    return usr_DllMain (hinst,reason,unused); \
  } struct _W32_dummy_strc_ ## FI {int i;}
#endif /* AUTOINIT_FUNCS_CALL_USR_DLLMAIN */
#endif /* _USRDLL */

#define _SET_INIT_AND_DEINIT_FUNCS(FI,FD) W32_SET_INIT_AND_DEINIT (FI,FD)
/* Indicate that automatic initialisers/deinitialisers are supported */
#define _AUTOINIT_FUNCS_ARE_SUPPORTED 1

#else  /* !__GNUC__ && !_MSC_FULL_VER */

/* Define EMIT_ERROR_IF_AUTOINIT_FUNCS_ARE_NOT_SUPPORTED before inclusion of header to
   abort compilation if automatic initialisers/deinitialisers are not supported */
#ifdef EMIT_ERROR_IF_AUTOINIT_FUNCS_ARE_NOT_SUPPORTED
#error \
  Compiler/platform does not support automatic calls of user-defined initializer and deinitializer
#endif /* EMIT_ERROR_IF_AUTOINIT_FUNCS_ARE_NOT_SUPPORTED */

/* Do nothing */
#define _SET_INIT_AND_DEINIT_FUNCS(FI,FD)
/* Indicate that automatic initialisers/deinitialisers are not supported */
#define _AUTOINIT_FUNCS_ARE_NOT_SUPPORTED 1

#endif /* !__GNUC__ && !_MSC_FULL_VER */
#endif /* !AUTOINIT_FUNCS_INCLUDED */