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Diffstat (limited to 'jni/iconv/woe32dll/export.h')
| -rw-r--r-- | jni/iconv/woe32dll/export.h | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/jni/iconv/woe32dll/export.h b/jni/iconv/woe32dll/export.h deleted file mode 100644 index 3e8a21f..0000000 --- a/jni/iconv/woe32dll/export.h +++ /dev/null @@ -1,106 +0,0 @@ -/* Exporting symbols from Cygwin shared libraries. - Copyright (C) 2006 Free Software Foundation, Inc. - Written by Bruno Haible <bruno@clisp.org>, 2006. - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or - (at your option) any later version. - - This program 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 General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. */ - -/* There are four ways to build shared libraries on Cygwin: - - - Export only functions, no variables. - This has the drawback of severely affecting the programming style in use. - It does not let the programmer use full ANSI C. It lets one platform - dictate the code style on all platforms. This is unacceptable. - - - Use the GNU ld --enable-auto-import option. It is the default on Cygwin - since July 2005. But it has three fatal drawbacks: - - It produces executables and shared libraries with relocations in the - .text segment, defeating the principles of virtual memory. - - For some constructs such as - extern int var; - int * const b = &var; - it creates an executable that will give an error at runtime, rather - than either a compile-time or link-time error or a working executable. - (This is with both gcc and g++.) Whereas this code, not relying on - auto-import: - extern __declspec (dllimport) int var; - int * const b = &var; - gives a compile-time error with gcc and works with g++. - - It doesn't work in some cases (references to a member field of an - exported struct variable, or to a particular element of an exported - array variable), requiring code modifications. Again one platform - dictates code modifications on all platforms. - - This is unacceptable. Therefore we disable this option, through the - woe32-dll.m4 autoconf macro. - - - Define a macro that expands to __declspec(dllexport) when building - the library and to __declspec(dllimport) when building code outside - the library, and use it in all header files of the library. - This is acceptable if - 1. the header files are unique to this library (not shared with - other packages), and - 2. the library sources are contained in one directory, making it easy - to define a -DBUILDING_LIBXYZ flag for the library. - Example: - #ifdef BUILDING_LIBASPRINTF - #define LIBASPRINTF_DLL_EXPORTED __declspec(dllexport) - #else - #define LIBASPRINTF_DLL_EXPORTED __declspec(dllimport) - #endif - - We use this technique for the libintl and the libasprintf libraries. - - - Define a macro that expands to __declspec(dllimport) always, and use - it in all header files of the library. Use an explicit export list for - the library. - This is acceptable if - 1. the programming language is not C++ (because the name mangling of - static struct/class fields and of variables in namespaces makes it - hard to maintain an export list). - The benefit of this approach is that the partitioning of the source files - into libraries (which source file goes into which library) does not - affect the source code; only the Makefiles reflect it. - The performance loss due to the unnecessary indirection for references - to variables from within the library defining the variable is acceptable. - - We use this technique for libgettextlib (because it contains many gnulib - modules) and for libgettextsrc (because this makes it easy to move source - code from an msg* program to libgettextsrc). The macro is called - DLL_VARIABLE. - - This file allows building an explicit export list. You can either - - specify the variables to be exported, and use the GNU ld option - --export-all-symbols to export all function names, or - - specify the variables and functions to be exported explicitly. - - Note: --export-all-symbols is the default when no other symbol is explicitly - exported. This means, the use of an explicit export on the variables has - the effect of no longer exporting the functions! - until the option - --export-all-symbols is used. */ - - /* IMP(x) is a symbol that contains the address of x. */ -#define IMP(x) _imp__##x - - /* Ensure that the variable x is exported from the library, and that a - pseudo-variable IMP(x) is available. */ -#define VARIABLE(x) \ - /* Export x without redefining x. This code was found by compiling a \ - snippet: \ - extern __declspec(dllexport) int x; int x = 42; */ \ - asm (".section .drectve\n"); \ - asm (".ascii \" -export:" #x ",data\"\n"); \ - asm (".data\n"); \ - /* Allocate a pseudo-variable IMP(x). */ \ - extern int x; \ - void * IMP(x) = &x; |