X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/1800689f23ce25c2f897081536ab39afcc692da4..75d9e502238df95fa53c0030b1fac0d4f43e4025:/docs/latex/wx/tlog.tex diff --git a/docs/latex/wx/tlog.tex b/docs/latex/wx/tlog.tex index 2b2fab3e84..f195d43ede 100644 --- a/docs/latex/wx/tlog.tex +++ b/docs/latex/wx/tlog.tex @@ -8,12 +8,13 @@ Classes: \helpref{wxLog}{wxlog},\\ \helpref{wxLogGui}{wxloggui},\\ \helpref{wxLogNull}{wxlognull},\\ \helpref{wxLogChain}{wxlogchain},\\ -\helpref{wxLogPassThrough}{wxlogpassthrough},\\ +\helpref{wxLogInterposer}{wxloginterposer},\\ +\helpref{wxLogInterposerTemp}{wxloginterposertemp},\\ \helpref{wxStreamToTextRedirector}{wxstreamtotextredirector} -This is a general overview of logging classes provided by wxWindows. The word +This is a general overview of logging classes provided by wxWidgets. The word logging here has a broad sense, including all of the program output, not only -non interactive messages. The logging facilities included in wxWindows provide +non-interactive messages. The logging facilities included in wxWidgets provide the base {\it wxLog} class which defines the standard interface for a {\it log target} as well as several standard implementations of it and a family of functions to use with them. @@ -35,17 +36,14 @@ message box to inform the user about it. \item{\bf wxLogWarning} for warnings - they are also normally shown to the user, but don't interrupt the program work. \item{\bf wxLogMessage} is for all normal, informational messages. They also -appear in a message box by default (but it can be changed, see below). Notice -that the standard behaviour is to not show informational messages if there are -any errors later - the logic being that the later error messages make the -informational messages preceding them meaningless. +appear in a message box by default (but it can be changed, see below). \item{\bf wxLogVerbose} is for verbose output. Normally, it is suppressed, but might be activated if the user wishes to know more details about the program progress (another, but possibly confusing name for the same function is {\bf wxLogInfo}). \item{\bf wxLogStatus} is for status messages - they will go into the status bar of the active or specified (as the first argument) \helpref{wxFrame}{wxframe} if it has one. -\item{\bf wxLogSysError} is mostly used by wxWindows itself, but might be +\item{\bf wxLogSysError} is mostly used by wxWidgets itself, but might be handy for logging errors after system call (API function) failure. It logs the specified message text as well as the last system error code ({\it errno} or {\it ::GetLastError()} depending on the platform) and @@ -68,8 +66,8 @@ to further restrict the amount of messages generated. The usage of these functions should be fairly straightforward, however it may be asked why not use the other logging facilities, such as C standard stdio functions or C++ streams. The short answer is that they're all very good -generic mechanisms, but are not really adapted for wxWindows, while the log -classes are. Some of advantages in using wxWindows log functions are: +generic mechanisms, but are not really adapted for wxWidgets, while the log +classes are. Some of advantages in using wxWidgets log functions are: \begin{itemize}\itemsep=0pt \item{\bf Portability} It is a common practice to use {\it printf()} @@ -91,7 +89,6 @@ You can also redirect the {\it wxLogXXX} calls to {\it cout} by just writing: Finally, there is also a possibility to redirect the output sent to {\it cout} to a \helpref{wxTextCtrl}{wxtextctrl} by using the \helpref{wxStreamToTextRedirector}{wxstreamtotextredirector} class. - \item{\bf Flexibility} The output of wxLog functions can be redirected or suppressed entirely based on their importance, which is either impossible or difficult to do with traditional methods. For example, only error messages, or @@ -100,10 +97,10 @@ informational messages. \item{\bf Completeness} Usually, an error message should be presented to the user when some operation fails. Let's take a quite simple but common case of a file error: suppose that you're writing your data file on disk and there is not -enough space. The actual error might have been detected inside wxWindows code +enough space. The actual error might have been detected inside wxWidgets code (say, in {\it wxFile::Write}), so the calling function doesn't really know the exact reason of the failure, it only knows that the data file couldn't be -written to the disk. However, as wxWindows uses {\it wxLogError()} in this +written to the disk. However, as wxWidgets uses {\it wxLogError()} in this situation, the exact error code (and the corresponding error message) will be given to the user together with "high level" message about data file writing error. @@ -113,7 +110,7 @@ After having enumerated all the functions which are normally used to log the messages, and why would you want to use them we now describe how all this works. -wxWindows has the notion of a {\it log target}: it is just a class deriving +wxWidgets has the notion of a {\it log target}: it is just a class deriving from \helpref{wxLog}{wxlog}. As such, it implements the virtual functions of the base class which are called when a message is logged. Only one log target is {\it active} at any moment, this is the one used by {\it wxLogXXX()} @@ -139,7 +136,7 @@ also be used without any change. There are: stderr by default as its name suggests. \item{\bf wxLogStream} This class has the same functionality as wxLogStderr, but uses {\it ostream} and cerr instead of {\it FILE *} and stderr. -\item{\bf wxLogGui} This is the standard log target for wxWindows +\item{\bf wxLogGui} This is the standard log target for wxWidgets applications (it is used by default if you don't do anything) and provides the most reasonable handling of all types of messages for given platform. \item{\bf wxLogWindow} This log target provides a "log console" which @@ -152,7 +149,7 @@ suppress output of {\it wxLogXXX()} functions. As an example, trying to open a non-existing file will usually provoke an error message, but if for some reasons it is unwanted, just use this construction: -{\small +{\small% \begin{verbatim} wxFile file; @@ -165,11 +162,11 @@ reasons it is unwanted, just use this construction: wxLogMessage("..."); // ok \end{verbatim} -} +}% \end{itemize} The log targets can also be combined: for example you may wish to redirect the messages somewhere else (for example, to a log file) but also process them as -normally. For this the \helpref{wxLogChain}{wxlogchain} and -\helpref{wxLogPassThrough}{wxlogpassthrough} can be used. +normally. For this the \helpref{wxLogChain}{wxlogchain}, \helpref{wxLogInterposer}{wxloginterposer} and\rtfsp +\helpref{wxLogInterposerTemp}{wxloginterposertemp} can be used.