/* * Copyright (C) 2006 Apple Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public License * along with this library; see the file COPYING.LIB. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * Boston, MA 02110-1301, USA. * */ #ifndef StaticConstructors_h #define StaticConstructors_h // We need to avoid having static constructors. We achieve this // with two separate methods for GCC and MSVC. Both methods prevent the static // initializers from being registered and called on program startup. On GCC, we // declare the global objects with a different type that can be POD default // initialized by the linker/loader. On MSVC we use a special compiler feature // to have the CRT ignore our static initializers. The constructors will never // be called and the objects will be left uninitialized. // // With both of these approaches, we must define and explicitly call an init // routine that uses placement new to create the objects and overwrite the // uninitialized placeholders. // // This is not completely portable, but is what we have for now without // changing how a lot of code accesses these global objects. #ifdef SKIP_STATIC_CONSTRUCTORS_ON_MSVC // - Assume that all includes of this header want ALL of their static // initializers ignored. This is currently the case. This means that if // a .cc includes this header (or it somehow gets included), all static // initializers after the include will not be executed. // - We do this with a pragma, so that all of the static initializer pointers // go into our own section, and the CRT won't call them. Eventually it would // be nice if the section was discarded, because we don't want the pointers. // See: http://msdn.microsoft.com/en-us/library/7977wcck(VS.80).aspx #pragma warning(disable:4075) #pragma init_seg(".unwantedstaticinits") #endif #ifndef SKIP_STATIC_CONSTRUCTORS_ON_GCC // Define an global in the normal way. #define DEFINE_GLOBAL(type, name, ...) \ const type name; #else // Define an correctly-sized array of pointers to avoid static initialization. // Use an array of pointers instead of an array of char in case there is some alignment issue. #define DEFINE_GLOBAL(type, name, ...) \ void * name[(sizeof(type) + sizeof(void *) - 1) / sizeof(void *)]; #endif #endif // StaticConstructors_h