Written by &name-dimitrie-paun; &email-dimitrie-paun;, 28 Mar 1998 (Extracted from wine/documentation/debug-msgs) It is possible to turn on and of debugging output from within the debugger using the set command. Please see the WineDbg Command Reference section for how to do this. At the end of the document, there is a "Style Guide" for debugging messages. Please read it. There are 4 types (or classes) of messages: FIXME Messages in this class are meant to signal unimplemented features, known bugs, etc. They serve as a constant and active reminder of what needs to be done. Examples: stubs, semi-implemented features, etc. ERR Messages in this class relate to serious errors in Wine. This sort of messages signal an inconsistent internal state, or more general, a condition which should never happen by design. Examples: unexpected change in internal state, etc. WARN These are warning messages. You should report a warning when something unwanted happen but the function behaves properly. That is, output a warning when you encounter something unexpected (ex: could not open a file) but the function deals correctly with the situation (that is, according to the docs). If you do not deal correctly with it, output a fixme. Examples: fail to access a resource required by the app. TRACE These are detailed debugging messages that are mainly useful to debug a component. These are usually turned off. Examples: everything else that does not fall in one of the above mentioned categories and the user does not need to know about it. To better manage the large volume of debugging messages that Wine can generate, we divide them also on a component basis. Each component is assigned a debugging channel. The identifier of the channel must be a valid C identifier but note that it may also be a reserved word like int or static. Examples of debugging channels: reg updown string We will refer to a generic channel as xxx. Typically, a file contains code pertaining to only one component, and as such, there is only one channel to output to. To simplify usage, you can declare that channel at the beginning of the file, and simply write FIXMEs, ERRs, etc. as such: #include "wine/debug.h" WINE_DEFAULT_DEBUG_CHANNEL(xxx); ... FIXME("some unimplemented feature", ...); ... if (zero != 0) ERR("This should never be non-null: %d", zero); ... In rare situations there is a need to output to more than one debug channel per file. In such cases, you need to declare all the additional channels at the top of the file, and use the _-version of the debugging macros: #include "wine/debug.h" WINE_DEFAULT_DEBUG_CHANNEL(xxx); WINE_DECLARE_DEBUG_CHANNEL(yyy); WINE_DECLARE_DEBUG_CHANNEL(zzz); ... FIXME("this one goes to xxx channel"); ... FIXME_(yyy)("Some other msg for the yyy channel"); ... WARN_(zzz)("And yet another msg on another channel!"); ... If you need to declare a new debugging channel, simply use it in your code. It will be picked up automatically by the build process. To test whether the debugging output of class yyy on channel xxx is enabled, use: TRACE_ON to test if TRACE is enabled WARN_ON to test if WARN is enabled FIXME_ON to test if FIXME is enabled ERR_ON to test if ERR is enabled Examples: if(TRACE_ON(atom)){ ...blah... } You should normally need to test only if TRACE_ON. At present, none of the other 3 tests (except for ERR_ON which is used only once!) are used in Wine. Resource identifiers can be either strings or numbers. To make life a bit easier for outputting these beasts (and to help you avoid the need to build the message in memory), I introduced a new function called debugres. The function is defined in wine/debug.h and has the following prototype: LPSTR debugres(const void *id); It takes a pointer to the resource id and returns a nicely formatted string of the identifier (which can be a string or a number, depending on the value of the high word). Numbers are formatted as such: #xxxx while strings as: 'some-string' Simply use it in your code like this: #include "wine/debug.h" ... TRACE("resource is %s", debugres(myresource)); The --debugmsg command line option controls the output of the debug messages. It has the following syntax: --debugmsg [yyy]#xxx[,[yyy1]#xxx1]* where # is either + or - when the optional class argument (yyy) is not present, then the statement will enable(+)/disable(-) all messages for the given channel (xxx) on all classes. For example: --debugmsg +reg,-file enables all messages on the reg channel and disables all messages on the file channel. when the optional class argument (yyy) is present, then the statement will enable (+)/disable(-) messages for the given channel (xxx) only on the given class. For example: --debugmsg trace+reg,warn-file enables trace messages on the reg channel and disables warning messages on the file channel. also, the pseudo-channel all is also supported and it has the intuitive semantics: --debugmsg +all -- enables all debug messages --debugmsg -all -- disables all debug messages --debugmsg yyy+all -- enables debug messages for class yyy on all channels. --debugmsg yyy-all -- disables debug messages for class yyy on all channels. So, for example: --debugmsg warn-all -- disables all warning messages. Also, note that at the moment: the FIXME and ERR classes are enabled by default the TRACE and WARN classes are disabled by default To compile out the debugging messages, provide configure with the following options: --disable-debug -- turns off TRACE, WARN, and FIXME (and DUMP). --disable-trace -- turns off TRACE only. This will result in an executable that, when stripped, is about 15%-20% smaller. Note, however, that you will not be able to effectively debug Wine without these messages. This feature has not been extensively tested--it may subtly break some things. This new scheme makes certain things more consistent but there is still room for improvement by using a common style of debug messages. Before I continue, let me note that the output format is the following: yyy:xxx:fff <message> where: yyy = the class (fixme, err, warn, trace) xxx = the channel (atom, win, font, etc) fff = the function name these fields are output automatically. All you have to provide is the <message> part. So here are some ideas: do NOT include the name of the function: it is included automatically if you want to output the parameters of the function, do it as the first thing and include them in parentheses, like this: TRACE("(%d, %p, ...)\n", par1, par2, ...); for stubs, you should output a FIXME message. I suggest this style: FIXME("(%x, %d, ...): stub\n", par1, par2, ...); try to output one line per message. That is, the format string should contain only one \n and it should always appear at the end of the string. (there are many reasons for this requirement, one of them is that each debug macro adds things to the beginning of the line) if you want to name a value, use = and NOT :. That is, instead of saying: FIXME("(fd: %d, file: %s): stub\n", fd, name); say: FIXME("(fd=%d, file=%s): stub\n", fd, name); use : to separate categories. try to avoid the style: FIXME(xxx, "(fd=%d, file=%s)\n", fd, name); instead use: FIXME(xxx, "(fd=%d, file=%s): stub\n", fd, name); The reason is that if you want to grep for things, you would search for FIXME but in the first case there is no additional information available, where in the second one, there is (e.g. the word stub) if you output a string s that might contain control characters, or if s may be NULL, use debugstr_a (for ASCII strings, or debugstr_w for Unicode strings) to convert s to a C string, like this: HANDLE32 WINAPI YourFunc(LPCSTR s) { FIXME("(%s): stub\n", debugstr_a(s)); } if you want to output a resource identifier, use debugres to convert it to a string first, like this: HANDLE32 WINAPI YourFunc(LPCSTR res) { FIXME("(res=%s): stub\n", debugres(s)); } if the resource identifier is a SEGPTR, use PTR_SEG_TO_LIN to get a liner pointer first: HRSRC16 WINAPI FindResource16( HMODULE16 hModule, SEGPTR name, SEGPTR type ) { [...] TRACE(resource, "module=%04x name=%s type=%s\n", hModule, debugres(PTR_SEG_TO_LIN(name)), debugres(PTR_SEG_TO_LIN(type)) ); [...] } for messages intended for the user (specifically those that report errors in the wine config file), use the MSG macro. Use it like a printf: MSG( "Definition of drive %d is incorrect!\n", drive ); However, note that there are very few valid uses of this macro. Most messages are debugging messages, so chances are you will not need to use this macro. Grep the source to get an idea where it is appropriate to use it. For structure dumps, use the DUMP macro. Use it like a printf, just like the MSG macro. Similarly, there are only a few valid uses of this macro. Grep the source to see when to use it.