This document should help new developers get started. Like all of Wine, it is a work in progress. SOURCE TREE STRUCTURE ===================== The Wine source tree is loosely based on the original Windows modules. Most of the source is concerned with implementing the Wine API, although there are also various tools, documentation, sample Winelib code, and code specific to the binary loader. Wine API directories: --------------------- KERNEL: files/ - file I/O loader/ - Win16-, Win32-binary loader memory/ - memory management msdos/ - DOS features and BIOS calls (interrupts) scheduler/ - process and thread management GDI: graphics/ - graphics drivers graphics/x11drv/ - X11 display driver graphics/metafiledrv/ - metafile driver objects/ - logical objects USER: controls/ - built-in widgets resources/ - built-in dialog resources windows/ - window management Other DLLs: dlls/*/ - Other system DLLs implemented by Wine Miscellaneous: misc/ - shell, registry, winsock, etc. multimedia/ - multimedia driver ipc/ - SysV IPC based interprocess communication win32/ - misc Win32 functions Tools: ------ rc/ - old resource compiler tools/ - relay code builder, new rc, etc. documentation/ - some documentation Binary loader specific directories: ----------------------------------- debugger/ - built-in debugger if1632/ - relay code miscemu/ - hardware instruction emulation graphics/win16drv/ - Win16 printer driver Winelib specific directories: ----------------------------- library/ - Required code for programs using Winelib libtest/ - Small samples and tests programs/ - Extended samples / system utilities IMPLEMENTING NEW API CALLS ========================== This is the simple version, and covers only Win32. Win16 is slightly uglier, because of the Pascal heritage and the segmented memory model. All of the Win32 APIs known to Wine are listed in [relay32/*.spec]. An unimplemented call will look like (from gdi32.spec) 269 stub PolyBezierTo To implement this call, you need to do the following four things. 1. Find the appropriate parameters for the call, and add a prototype to [include/windows.h]. In this case, it might look like BOOL32 WINAPI PolyBezierTo32(HDC32, LPCVOID, DWORD); #define PolyBezierTo WINELIB_NAME(PolyBezierTo) Note the use of the #define for Winelib. See below for discussion of function naming conventions. 2. Modify the .spec file to tell Wine that the function has an implementation, what the parameters look like and what Wine function to use for the implementation. In Win32, things are simple--everything is 32-bits. However, the relay code handles pointers and pointers to strings slightly differently, so you should use 'str' and 'wstr' for strings, 'ptr' for other pointer types, and 'long' for everything else. 269 stdcall PolyBezierTo(long ptr long) PolyBezierTo32 The 'PolyBezierTo32' at the end of the line is which Wine function to use for the implementation. 3. Implement the function as a stub. Once you add the function to the .spec file, you must add the function to the Wine source before it will link. Add a function called 'PolyBezierTo32' somewhere. Good things to put into a stub: o a correct prototype, including the WINAPI o header comments, including full documentation for the function and arguments o A FIXME message and an appropriate return value are good things to put in a stub. /************************************************************ * PolyBezierTo32 (GDI32.269) Draw many Bezier curves * * BUGS * Unimplemented */ BOOL32 WINAPI PolyBezierTo32(HDC32 hdc, LPCVOID p, DWORD count) { /* tell the user they've got a substandard implementation */ FIXME(gdi, ":(%x,%p,%d): stub\n", hdc, p, count); /* some programs may be able to compensate, if they know what happened */ SetLastError(ERROR_CALL_NOT_IMPLEMENTED); return FALSE; /* error value */ } 4. Implement and test the function. MEMORY AND SEGMENTS =================== NE (Win16) executables consist of multiple segments. The Wine loader loads each segment into a unique location in the Wine processes memory and assigns a selector to that segment. Because of this, it's not possible to exchange addresses freely between 16-bit and 32-bit code. Addresses used by 16-bit code are segmented addresses (16:16), formed by a 16-bit selector and a 16-bit offset. Those used by the Wine code are regular 32-bit linear addresses. There are four ways to obtain a segmented pointer: - Use the SEGPTR_* macros in include/heap.h (recommended). - Allocate a block of memory from the global heap and use WIN16_GlobalLock to get its segmented address. - Allocate a block of memory from a local heap, and build the segmented address from the local heap selector (see the USER_HEAP_* macros for an example of this). - Declare the argument as 'segptr' instead of 'ptr' in the spec file for a given API function. Once you have a segmented pointer, it must be converted to a linear pointer before you can use it from 32-bit code. This can be done with the PTR_SEG_TO_LIN() and PTR_SEG_OFF_TO_LIN() macros. The linear pointer can then be used freely with standard Unix functions like memcpy() etc. without worrying about 64k boundaries. Note: there's no easy way to convert back from a linear to a segmented address. In most cases, you don't need to worry about segmented address, as the conversion is made automatically by the callback code and the API functions only see linear addresses. However, in some cases it is necessary to manipulate segmented addresses; the most frequent cases are: - API functions that return a pointer - lParam of Windows messages that point to a structure - Pointers contained inside structures accessed by 16-bit code. It is usually a good practice to used the type 'SEGPTR' for segmented pointers, instead of something like 'LPSTR' or 'char *'. As SEGPTR is defined as a DWORD, you'll get a compilation warning if you mistakenly use it as a regular 32-bit pointer. STRUCTURE PACKING ================= Under Windows, data structures are tightly packed, i.e. there is no padding between structure members. On the other hand, by default gcc aligns structure members (e.g. WORDs are on a WORD boundary, etc.). This means that a structure like struct { BYTE x; WORD y; }; will take 3 bytes under Windows, but 4 with gcc, because gcc will add a dummy byte between x and y. To have the correct layout for structures used by Windows code, you need to use the WINE_PACKED attribute; so you would declare the above structure like this: struct { BYTE x; WORD y WINE_PACKED; }; You have to do this every time a structure member is not aligned correctly under Windows (i.e. a WORD not on an even address, or a DWORD on a address that is not a multiple of 4). NAMING CONVENTIONS FOR API FUNCTIONS AND TYPES ============================================== In order to support both Win16 and Win32 APIs within the same source code, the following convention must be used in naming all API functions and types. If the Windows API uses the name 'xxx', the Wine code must use: - 'xxx16' for the 16-bit version, - 'xxx32' for the 32-bit version when no ASCII/Unicode strings are involved, - 'xxx32A' for the 32-bit version with ASCII strings, - 'xxx32W' for the 32-bit version with Unicode strings. You should then use the macros WINELIB_NAME[_AW](xxx) or DECL_WINELIB_TYPE[_AW](xxx) (defined in include/wintypes.h) to define the correct 'xxx' function or type for Winelib. When compiling Wine itself, 'xxx' is _not_ defined, meaning that code inside of Wine must always specify explicitly the 16-bit or 32-bit version. If 'xxx' is the same in Win16 and Win32, or if 'xxx' is Win16 only, you can simply use the same name as Windows, i.e. just 'xxx'. If 'xxx' is Win32 only, you can use 'xxx' if there are no strings involved, otherwise you must use the 'xxx32A' and 'xxx32W' forms. Examples: typedef short INT16; typedef int INT32; DECL_WINELIB_TYPE(INT); typedef struct { /* Win32 ASCII data structure */ } WNDCLASS32A; typedef struct { /* Win32 Unicode data structure */ } WNDCLASS32W; typedef struct { /* Win16 data structure */ } WNDCLASS16; DECL_WINELIB_TYPE_AW(WNDCLASS); ATOM RegisterClass16( WNDCLASS16 * ); ATOM RegisterClass32A( WNDCLASS32A * ); ATOM RegisterClass32W( WNDCLASS32W * ); #define RegisterClass WINELIB_NAME_AW(RegisterClass) The Winelib user can then say: INT i; WNDCLASS wc = { ... }; RegisterClass( &wc ); and this will use the correct declaration depending on the definition of the symbols WINELIB and UNICODE. API ENTRY POINTS ================ Because Win16 programs use a 16-bit stack and because they can only call 16:16 addressed functions, all API entry points must be at low address offsets and must have the arguments translated and moved to Wines 32-bit stack. This task is handled by the code in the "if1632" directory. To define a new API entry point handler you must place a new entry in the appropriate API specification file. These files are named *.spec. For example, the API specification file for the USER DLL is contained in the file user.spec. These entries are processed by the "build" program to create an assembly file containing the entry point code for each API call. The format of the *.spec files is documented in the file "tools/build-spec.txt". DEBUG MESSAGES ============== To display a message only during debugging, you normally write something like this: TRACE(win,"abc..."); or FIXME(win,"abc..."); or WARN(win,"abc..."); or ERR(win,"abc..."); depending on the seriousness of the problem. (documentation/degug-msgs explains when it is appropriate to use each of them) These macros are defined in include/debug.h. The macro-definitions are generated by the shell-script tools/make_debug. It scans the source code for symbols of this forms and puts the necessary macro definitions in include/debug.h and include/debugdefs.h. These macros test whether the debugging "channel" associated with the first argument of these macros (win in the above example) is enabled and thus decide whether to actually display the text. In addition you can change the types of displayed messages by supplying the "-debugmsg" option to Wine. If your debugging code is more complex than just printf, you can use the symbols TRACE_ON(xxx), WARN_ON(xxx), ERR_ON(xxx) and FIXME_ON(xxx) as well. These are true when channel xxx is enabled, either permanent or in the command line. Thus, you can write: if(TRACE_ON(win))DumpSomeStructure(&str); Don't worry about the inefficiency of the test. If it is permanently disabled (that is TRACE_ON(win) is 0 at compile time), the compiler will eliminate the dead code. You have to start tools/make_debug only if you introduced a new macro, e.g. TRACE(win32). For more info about debugging messages, read: documentation/debug-msgs MORE INFO ========= 1. There is a FREE online version of the MSDN library (including documentation for the Win32 API) on http://www.microsoft.com/msdn/ 2. http://www.sonic.net/~undoc/bookstore.html 3. In 1993 Dr. Dobbs Journal published a column called "Undocumented Corner". 4. You might want to check out BYTE from December 1983 as well :-)