\section{\class{wxLog}}\label{wxlog} wxLog class defines the interface for the {\it log targets} used by wxWindows logging functions as explained in the \helpref{wxLog overview}{wxlogoverview}. The only situations when you need to directly use this class is when you want to derive your own log target because the existing ones don't satisfy your needs. Another case is if you wish to customize the behaviour of the standard logging classes (all of which respect the wxLog settings): for example, set which trace messages are logged and which are not or change (or even remove completely) the timestamp on the messages. Otherwise, it is completely hidden behind the {\it wxLogXXX()} functions and you may not even know about its existence. See \helpref{log overview}{wxlogoverview} for the descriptions of wxWindows logging facilities. \wxheading{Derived from} No base class \wxheading{Include files} \latexignore{\rtfignore{\wxheading{Function groups}}} \membersection{Static functions} The functions in this section work with and manipulate the active log target. The {\it OnLog()} is called by the {\it wxLogXXX()} functions and invokes the {\it DoLog()} of the active log target if any. Get/Set methods are used to install/query the current active target and, finally, {\it DontCreateOnDemand()} disables the automatic creation of a standard log target if none actually exists. It is only useful when the application is terminating and shouldn't be used in other situations because it may easily lead to a loss of messages. \helpref{OnLog}{wxlogonlog}\\ \helpref{GetActiveTarget}{wxloggetactivetarget}\\ \helpref{SetActiveTarget}{wxlogsetactivetarget}\\ \helpref{DontCreateOnDemand}{wxlogdontcreateondemand} \membersection{Message buffering} Some of wxLog implementations, most notably the standard wxLogGui class, buffer the messages (for example, to avoid showing the user a zillion of modal message boxes one after another - which would be really annoying). {\it Flush()} shows them all and clears the buffer contents. Although this function doesn't do anything if the buffer is already empty, {\it HasPendingMessages()} is also provided which allows to explicitly verify it. \helpref{Flush}{wxlogflush}\\ \helpref{HasPendingMessages}{haspendingmessages} \membersection{Customization}\label{wxlogcustomization} The functions below allow some limited customization of wxLog behaviour without writing a new log target class (which, aside of being a matter of several minutes, allows you to do anything you want). The verbose messages are the trace messages which are not disabled in the release mode and are generated by {\it wxLogVerbose()}. They are not normally shown to the user because they present little interest, but may be activated, for example, in order to help the user find some program problem. As for the (real) trace messages, they come in different kinds: \begin{itemize}\itemsep=0pt \item{wxTraceMemAlloc} for the messages about creating and deleting objects \item{wxTraceMessages} for tracing the windowing system messages/events \item{wxTraceResAlloc} for allocating and releasing the system ressources \item{wxTraceRefCount} for reference counting related messages \item{wxTraceOleCalls} for the OLE (or COM) method invocations (wxMSW only) \item{other} the remaining bits are free for user-defined trace levels \end{itemize} The trace mask is a bit mask which tells which (if any) of these trace messages are going to be actually logged. For the trace message to appear somewhere, all the bits in the mask used in the call to {\it wxLogTrace()} function must be set in the current trace mask. For example, \begin{verbatim} wxLogTrace(wxTraceRefCount | wxTraceOle, "Active object ref count: %d", nRef); \end{verbatim} will do something only if the current trace mask contains both wxTraceRefCount and wxTraceOle. Finally, the {\it wxLog::DoLog()} function automatically prepends a time stamp to all the messages. The format of the time stamp may be changed: it can be any string with \% specificators fully described in the documentation of the standard {\it strftime()} function. For example, the default format is "[\%d/\%b/\%y \%H:\%M:\%S] " which gives something like "[17/Sep/98 22:10:16] " (without quotes) for the current date. Setting an empty string as the time format disables timestamping of the messages completely. \helpref{SetVerbose}{wxlogsetverbose}\\ \helpref{GetVerbose}{wxloggetverbose}\\ \helpref{SetTimeStampFormat}{wxlogsettimestampformat}\\ \helpref{GetTimeStampFormat}{wxloggettimestampformat}\\ \helpref{SetTraceMask}{wxlogsettracemask}\\ \helpref{GetTraceMask}{wxloggettracemask} %%%%% MEMBERS HERE %%%%% \helponly{\insertatlevel{2}{ \wxheading{Members} }} \membersection{wxLog::OnLog}\label{wxlogonlog} \func{static void}{OnLog}{\param{wxLogLevel }{ level}, \param{const char * }{ message}} Forwards the message at specified level to the {\it DoLog()} function of the active log target if there is any, does nothing otherwise. \membersection{wxLog::GetActiveTarget}\label{wxloggetactivetarget} \func{static wxLog *}{GetActiveTarget}{\void} Returns the pointer to the active log target (may be NULL). \membersection{wxLog::SetActiveTarget}\label{wxlogsetactivetarget} \func{static wxLog *}{SetActiveTarget}{\param{wxLog * }{ logtarget}} Sets the specified log target as the active one. Returns the pointer to the previous active log target (may be NULL). \membersection{wxLog::DontCreateOnDemand}\label{wxlogdontcreateondemand} \func{static void}{DontCreateOnDemand}{\void} Instructs wxLog to not create new log targets on the fly if there is none currently. (Almost) for internal use only. \membersection{wxLog::Flush}\label{wxlogflush} \func{virtual void}{Flush}{\void} Shows all the messages currently in buffer and clears it. If the buffer is already empty, nothing happens. \membersection{wxLog::HasPendingMessages}\label{haspendingmessages} \constfunc{bool}{HasPendingMessages}{\void} Returns true if there are any messages in the buffer (not yet shown to the user). (Almost) for internal use only. \membersection{wxLog::SetVerbose}\label{wxlogsetverbose} \func{void}{SetVerbose}{\param{bool }{ verbose = TRUE}} Activates or desactivates verbose mode in which the verbose messages are logged as the normal ones instead of being silently dropped. \membersection{wxLog::GetVerbose}\label{wxloggetverbose} \constfunc{bool}{GetVerbose}{\void} Returns whether the verbose mode is currently active. \membersection{wxLog::SetTimeStampFormat}\label{wxlogsettimestampformat} \func{void}{SetTimeStampFormat}{\param{const char * }{ format}} Sets the timestamp format prepended by the default log targets to all messages. The string may contain any normal characters as well as \% prefixed format specificators, see {\it strftime()} manual for details. Passing an empty string to this function disables message timestamping. \membersection{wxLog::GetTimeStampFormat}\label{wxloggettimestampformat} \constfunc{const char *}{GetTimeStampFormat}{\void} Returns the current timestamp format string. \membersection{wxLog::SetTraceMask}\label{wxlogsettracemask} \func{static void}{SetTraceMask}{\param{wxTraceMask }{ mask}} Sets the trace mask, see \helpref{Customization}{wxlogcustomization} section for details. \membersection{wxLog::GetTraceMask}\label{wxloggettracemask} Returns the current trace mask, see \helpref{Customization}{wxlogcustomization} section for details.