C++ shl_unload函数代码示例

int main ()
{
  shl_t  solib_handle;
  int  dummy;
  int  status;
  int  (*solib_main) (int);

  /* Load a shlib, with immediate binding of all symbols.

     Note that the pathname of the loaded shlib is assumed to be relative
     to the testsuite directory (from whence the tested GDB is run), not
     from dot/.
   */
  dummy = 1;  /* Put some code between shl_ calls... */
  solib_handle = shl_load ("gdb.base/solib1.sl", BIND_IMMEDIATE, 0);

  /* Find a function within the shlib, and call it. */
  status = shl_findsym (&solib_handle,
                        "solib_main",
                        TYPE_PROCEDURE,
                        (long *) &solib_main);
  status = (*solib_main) (dummy);

  /* Unload the shlib. */
  status = shl_unload (solib_handle);

  /* Load a different shlib, with deferred binding of all symbols. */
  dummy = 2;
  solib_handle = shl_load ("gdb.base/solib2.sl", BIND_DEFERRED, 0);

  /* Find a function within the shlib, and call it. */
  status = shl_findsym (&solib_handle,
                        "solib_main",
                        TYPE_PROCEDURE,
                        (long *) &solib_main);
  status = (*solib_main) (dummy);

  /* Unload the shlib. */
  status = shl_unload (solib_handle);

  /* Reload the first shlib again, with deferred symbol binding this time. */
  dummy = 3;
  solib_handle = shl_load ("gdb.base/solib1.sl", BIND_IMMEDIATE, 0);

  /* Unload it without trying to find any symbols in it. */
  status = shl_unload (solib_handle);

  /* All done. */
  dummy = -1;
  return 0;
}

ppl_status_t
ppl_dso_unload (ppl_dso_handle_t * thedso)
{
  ppl_dso_handle_t *dso = thedso;

  if (dso->handle == NULL)
    {
      osip_free (dso);
      return PPL_SUCCESS;
    }
#if defined(DSO_USE_SHL)
  shl_unload ((shl_t) dso->handle);
#elif defined(DSO_USE_DYLD)
  NSUnLinkModule (dso->handle, FALSE);
#elif defined(DSO_USE_DLFCN)
  if (dlclose (dso->handle) != 0)
    {
      osip_free (dso);
      return PPL_EINIT;
    }
#endif
  dso->handle = NULL;
  osip_free (dso);
  return PPL_SUCCESS;
}

int
dlclose(dll_handle h)
{
    shl_t hp = *((shl_t *)h);
    if (hp != NULL) free(hp);
    return shl_unload(h);
}

static int dl_load(DSO *dso, const char *filename)
	{
	shl_t ptr;
	char translated[DSO_MAX_TRANSLATED_SIZE];
	int len;

	/* The same comment as in dlfcn_load applies here. bleurgh. */
	len = strlen(filename) + strlen(extension);
	if((dso->flags & DSO_FLAG_NAME_TRANSLATION) &&
			(len + 3 < DSO_MAX_TRANSLATED_SIZE) &&
			(strstr(filename, "/") == NULL))
		{
		sprintf(translated, "lib%s%s", filename, extension);
		ptr = shl_load(translated, BIND_IMMEDIATE, NULL);
		}
	else
		ptr = shl_load(filename, BIND_IMMEDIATE, NULL);
	if(ptr == NULL)
		{
		DSOerr(DSO_F_DL_LOAD,DSO_R_LOAD_FAILED);
		return(0);
		}
	if(!sk_push(dso->meth_data, (char *)ptr))
		{
		DSOerr(DSO_F_DL_LOAD,DSO_R_STACK_ERROR);
		shl_unload(ptr);
		return(0);
		}
	return(1);
	}

void *dlopen(const char *fname, int mode)
{
  shl_t handle;
  LibEntry entry = NULL;

  dlerrno = 0;
  if (fname == NULL)
    handle = PROG_HANDLE;
  else {
    handle = shl_load(fname, mode | BIND_VERBOSE, 0L);
    if (handle != NULL) {
      if ((entry = find_lib_entry(handle)) == NULL) {
	if ((entry = new_lib_entry(handle)) == NULL) {
	  shl_unload(handle);
	  handle = NULL;
	}
      }
      else
	increment_lib_entry_count(entry);
    }
    if (handle == NULL) {
      dlerrno = 1;
      sprintf(errbuf, "can't open %s", fname);
    }
  }
#ifdef DEBUG
  printf("opening library %s, handle = %x, count = %d\n",
	 fname, handle, entry ? lib_entry_count(entry) : -1);
  if (dlerrno) printf("%s\n", dlerror());
#endif
  return (void *) handle;
}

int dlclose(void *handle)
{
  LibEntry entry;
#ifdef DEBUG
  entry = find_lib_entry(handle);
  printf("closing library handle = %x, count = %d\n",
	 handle, entry ? lib_entry_count(entry) : -1);
#endif

  dlerrno = 0;
  if ((shl_t) handle == PROG_HANDLE)
    return 0; /* ignore attempts to close main program */
  else {

    if ((entry = find_lib_entry((shl_t) handle)) != NULL) {
      decrement_lib_entry_count(entry);
      if (lib_entry_count(entry) > 0)
	return 0;
      else {
	/* unload once reference count reaches zero */
	free_lib_entry(entry);
	if (shl_unload((shl_t) handle) == 0)
	  return 0;
      }
    }
    /* if you get to here, an error has occurred */
    dlerrno = 1;
    sprintf(errbuf, "attempt to close library failed");
#ifdef DEBUG
    printf("%s\n", dlerror());
#endif
    return -1;
  }
}

bool QLibraryPrivate::unload_sys()
{
    if (shl_unload((shl_t)pHnd)) {
        qWarning("QLibrary: Cannot unload %s", QFile::encodeName(fileName).constData());
        return false;
    }
    return true;
}

void 
unloadSharedObject (void *object) {
#ifdef HAVE_SHL_LOAD
  if (shl_unload(object) == -1)
    logMessage(LOG_ERR, "Shared library unload error: %s",
               strerror(errno));
#endif /* HAVE_SHL_LOAD */
}

static void dClose(void * handle)
{
#ifdef __hpux
       shl_unload(handle);
#else
       dlclose(handle);
#endif
}

void
sane_exit (void)
{
  struct backend *be, *next;
  struct alias *alias;

  DBG(2, "sane_exit: exiting\n");

  for (be = first_backend; be; be = next)
    {
      next = be->next;
      if (be->loaded)
        {
          DBG(3, "sane_exit: calling backend `%s's exit function\n", be->name);
          (*be->op[OP_EXIT]) ();
#ifdef HAVE_DLL

#ifdef HAVE_DLOPEN
          if (be->handle)
            dlclose (be->handle);
#elif defined(HAVE_SHL_LOAD)
          if (be->handle)
            shl_unload(be->handle);
#else
# error "Tried to compile unsupported DLL."
#endif /* HAVE_DLOPEN */

#endif /* HAVE_DLL */
        }
      if (!be->permanent)
        {
          if (be->name)
            free ((void *) be->name);
          free (be);
        }
    }
  first_backend = 0;

  while( (alias = first_alias) != NULL )
    {
      first_alias = first_alias->next;
      free(alias->oldname);
      free(alias);
    }

  if (NULL != devlist)
    { /* Release memory allocated by sane_get_devices(). */
      int i = 0;
      while (devlist[i])
        free(devlist[i++]);
      free(devlist);

      devlist = NULL;
      devlist_size = 0;
      devlist_len = 0;
    }
  DBG(3, "sane_exit: finished\n");
}

void ap_os_dso_unload(void *handle) 
{
#if defined(HPUX) || defined(HPUX10)
    shl_unload((shl_t)handle);
#else
    dlclose(handle);
#endif
    return;
}

bool QLibraryPrivate::unload_sys()
{
#if !defined(QT_NO_DYNAMIC_LIBRARY)
#  if defined(QT_HPUX_LD)
    if (shl_unload((shl_t)pHnd)) {
#  else
    if (dlclose(pHnd)) {
#  endif
        errorString = QLibrary::tr("Cannot unload library %1: %2").arg(fileName).arg(qdlerror());
        return false;
    }
#endif
    errorString.clear();
    return true;
}

#ifdef Q_OS_LINUX
Q_CORE_EXPORT QFunctionPointer qt_linux_find_symbol_sys(const char *symbol)
{
    return QFunctionPointer(dlsym(RTLD_DEFAULT, symbol));
}
#endif

#ifdef Q_OS_MAC
Q_CORE_EXPORT QFunctionPointer qt_mac_resolve_sys(void *handle, const char *symbol)
{
    return QFunctionPointer(dlsym(handle, symbol));
}
#endif

QFunctionPointer QLibraryPrivate::resolve_sys(const char* symbol)
{
#if defined(QT_AOUT_UNDERSCORE)
    // older a.out systems add an underscore in front of symbols
    char* undrscr_symbol = new char[strlen(symbol)+2];
    undrscr_symbol[0] = '_';
    strcpy(undrscr_symbol+1, symbol);
    QFunctionPointer address = QFunctionPointer(dlsym(pHnd, undrscr_symbol));
    delete [] undrscr_symbol;
#elif defined(QT_HPUX_LD)
    QFunctionPointer address = 0;
    if (shl_findsym((shl_t*)&pHnd, symbol, TYPE_UNDEFINED, &address) < 0)
        address = 0;
#elif defined (QT_NO_DYNAMIC_LIBRARY)
    QFunctionPointer address = 0;
#else
    QFunctionPointer address = QFunctionPointer(dlsym(pHnd, symbol));
#endif
    if (!address) {
        errorString = QLibrary::tr("Cannot resolve symbol \"%1\" in %2: %3").arg(
                          QString::fromLatin1(symbol)).arg(fileName).arg(qdlerror());
    } else {
        errorString.clear();
    }
    return address;
}

static void
_g_module_close (gpointer handle,
                 gboolean is_unref)
{
    if (!is_unref)
    {
        if (shl_unload ((shl_t) handle) != 0)
            g_module_set_error (g_strerror (errno));
    }
}

/******************************************************************
 *
 * Porting Free library function to different platforms 
 *
 *******************************************************************/
void myFreeLibrary(HINSTANCE hKVFILTER)
{
#if defined(_WINDOWS)
     FreeLibrary( hKVFILTER );
#elif defined(_HPUX11)
     shl_unload((shl_t)hKVFILTER);
#else
     dlclose(hKVFILTER);
#endif
}

void
TclpUnloadFile(
    Tcl_LoadHandle loadHandle)	/* loadHandle returned by a previous call to
				 * TclpDlopen(). The loadHandle is a token
				 * that represents the loaded file. */
{
    shl_t handle;

    handle = (shl_t) loadHandle;
    shl_unload(handle);
}