This is intended to be a document to help new developers get started. Existing developers should feel free to add their comments. SOURCE TREE STRUCTURE ===================== Source tree is loosely based on the original Windows modules. Most directories are shared between the binary emulator and the library. Shared directories: ------------------- KERNEL: files/ - file I/O loader/ - Win16-, Win32-binary loader memory/ - memory management msdos/ - DOS and BIOS emulation 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 Miscellaneous: misc/ - shell, registry, winsock, etc... multimedia/ - multimedia driver ipc/ - SysV IPC management win32/ - misc Win32 functions Tools: rc/ - resource compiler tools/ - relay code builder + misc tools documentation/ - some documentation Emulator-specific directories: ------------------------------ debugger/ - built-in debugger if1632/ - relay code miscemu/ - hardware instruction emulation graphics/win16drv/ - Win16 printer driver Winelib-specific directories: ----------------------------- library/ - Winelib-specific routines (should disappear) programs/ - utilities (Progman, WinHelp) libtest/ - Winelib test samples 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, as well as share the include files between the emulator and the library, 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 the emulator, 'xxx' is _not_ defined, meaning that you must always specify explicitly whether you want the 16-bit or 32-bit version. Note: if 'xxx' is the same in Win16 and Win32, you can simply use the same name as Windows. 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 WINELIB16, WINELIB32 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 :-)