text: // Copyright (C) 2016 and later: Unicode, Inc. and others.
  // License & terms of use: http://www.unicode.org/copyright.html
  /*
  ******************************************************************************
  *
  * Copyright (C) 2009-2011, International Business Machines
  *                Corporation and others. All Rights Reserved.
  *
  ******************************************************************************
  *   file name:  ucln_imp.h
  *   encoding:   US-ASCII
  *   tab size:   8 (not used)
  *   indentation:4
  *
  *   This file contains the platform specific implementation of per-library cleanup.
  *
  */
  
  
  #ifndef __UCLN_IMP_H__
  #define __UCLN_IMP_H__
  
  #include "ucln.h"
  #include <stdlib.h>
  
  /**
   * Auto cleanup of ICU libraries
   * There are several methods in per library cleanup of icu libraries:
   * 1) Compiler/Platform based cleanup:
   *   a) Windows MSVC uses DllMain()
   *   b) GCC uses destructor function attribute
   *   c) Sun Studio, AIX VA, and HP-UX aCC uses a linker option to set the exit function
   * 2) Using atexit()
   * 3) Implementing own automatic cleanup functions
   *
   * For option 1, ensure that UCLN_NO_AUTO_CLEANUP is set to 0 by using --enable-auto-cleanup
   * configure option or by otherwise setting UCLN_NO_AUTO_CLEANUP to 0
   * For option 2, follow option 1 and also define UCLN_AUTO_ATEXIT
   * For option 3, follow option 1 and also define UCLN_AUTO_LOCAL (see below for more information)
   */
  
  #if !UCLN_NO_AUTO_CLEANUP
  
  /*
   * The following declarations are for when UCLN_AUTO_LOCAL or UCLN_AUTO_ATEXIT
   * are defined. They are commented out because they are static and will be defined
   * later. The information is still here to provide some guidance for the developer
   * who chooses to use UCLN_AUTO_LOCAL.
   */
  /**
   * Give the library an opportunity to register an automatic cleanup.
   * This may be called more than once.
   */
  /*static void ucln_registerAutomaticCleanup();*/
  /**
   * Unregister an automatic cleanup, if possible. Called from cleanup.
   */
  /*static void ucln_unRegisterAutomaticCleanup();*/
  
  #ifdef UCLN_TYPE_IS_COMMON
  #   define UCLN_CLEAN_ME_UP u_cleanup()
  #else
  #   define UCLN_CLEAN_ME_UP ucln_cleanupOne(UCLN_TYPE)
  #endif
  
  /* ------------ automatic cleanup: registration. Choose ONE ------- */
  #if defined(UCLN_AUTO_LOCAL)
  /* To use:
   *  1. define UCLN_AUTO_LOCAL,
   *  2. create ucln_local_hook.c containing implementations of
   *           static void ucln_registerAutomaticCleanup()
   *           static void ucln_unRegisterAutomaticCleanup()
   */
  #include "ucln_local_hook.c"
  
  #elif defined(UCLN_AUTO_ATEXIT)
  /*
   * Use the ANSI C 'atexit' function. Note that this mechanism does not
   * guarantee the order of cleanup relative to other users of ICU!
   */
  static UBool gAutoCleanRegistered = FALSE;
  
  static void ucln_atexit_handler()
  {
      UCLN_CLEAN_ME_UP;
  }
  
  static void ucln_registerAutomaticCleanup()
  {
      if(!gAutoCleanRegistered) {
          gAutoCleanRegistered = TRUE;
          atexit(&ucln_atexit_handler);
      }
  }
  
  static void ucln_unRegisterAutomaticCleanup () {
  }
  /* ------------end of automatic cleanup: registration. ------- */
  
  #elif defined (UCLN_FINI)
  /**
   * If UCLN_FINI is defined, it is the (versioned, etc) name of a cleanup
   * entrypoint. Add a stub to call ucln_cleanupOne
   * Used on AIX, Solaris, and HP-UX
   */
  U_CAPI void U_EXPORT2 UCLN_FINI (void);
  
  U_CAPI void U_EXPORT2 UCLN_FINI ()
  {
      /* This function must be defined, if UCLN_FINI is defined, else link error. */
       UCLN_CLEAN_ME_UP;
  }
  
  /* Windows: DllMain */
  #elif U_PLATFORM_HAS_WIN32_API
  /* 
   * ICU's own DllMain.
   */
  
  /* these are from putil.c */
  /* READ READ READ READ!    Are you getting compilation errors from windows.h?
            Any source file which includes this (ucln_imp.h) header MUST 
            be defined with language extensions ON. */
  #   define WIN32_LEAN_AND_MEAN
  #   define VC_EXTRALEAN
  #   define NOUSER
  #   define NOSERVICE
  #   define NOIME
  #   define NOMCX
  #   include <windows.h>
  /*
   * This is a stub DllMain function with icu specific process handling code.
   */
  BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
  {
      BOOL status = TRUE;
  
      switch(fdwReason) {
          case DLL_PROCESS_ATTACH:
               /* ICU does not trap process attach, but must pass these through properly. */
              /* ICU specific process attach could go here */
              break;
  
          case DLL_PROCESS_DETACH:
              /* Here is the one we actually care about. */
  
              UCLN_CLEAN_ME_UP;
  
              break;
  
          case DLL_THREAD_ATTACH:
              /* ICU does not trap thread attach, but must pass these through properly. */
              /* ICU specific thread attach could go here */
              break;
  
          case DLL_THREAD_DETACH:
              /* ICU does not trap thread detach, but must pass these through properly. */
              /* ICU specific thread detach could go here */
              break;
  
      }
      return status;
  }
  
  #elif defined(__GNUC__)
  /* GCC - use __attribute((destructor)) */
  static void ucln_destructor()   __attribute__((destructor)) ;
  
  static void ucln_destructor() 
  {
      UCLN_CLEAN_ME_UP;
  }
  
  #endif
  
  #endif /* UCLN_NO_AUTO_CLEANUP */
  
  #else
  #error This file can only be included once.
  #endif
  