on Linux, not GTK

[wxWidgets.git] / docs / latex / wx / tlog.tex

diff --git a/docs/latex/wx/tlog.tex b/docs/latex/wx/tlog.tex
index 0cdc28760775c2d531a6142edb50f6fa24cda434..2b2fab3e840456ed564829e63df3a027e07e1b16 100644 (file)
--- a/docs/latex/wx/tlog.tex
+++ b/docs/latex/wx/tlog.tex
@@ -1,10 +1,15 @@
-\section{Log classes overview}\label{wxlogoverview}
+\section{wxLog classes overview}\label{wxlogoverview}

 
 

-Classes: \helpref{wxLog}{wxlog}\\
+Classes: \helpref{wxLog}{wxlog},\\

 \helpref{wxLogStderr}{wxlogstderr},\\
 \helpref{wxLogStderr}{wxlogstderr},\\

-\helpref{wxLogOstream}{wxlogostream}, \helpref{wxLogTextCtrl}{wxlogtextctrl},\\
-\helpref{wxLogWindow}{wxlogwindow}, \helpref{wxLogGui}{wxloggui},\\
-\helpref{wxLogNull}{wxlognull}
+\helpref{wxLogStream}{wxlogstream},\\
+\helpref{wxLogTextCtrl}{wxlogtextctrl},\\
+\helpref{wxLogWindow}{wxlogwindow},\\
+\helpref{wxLogGui}{wxloggui},\\
+\helpref{wxLogNull}{wxlognull},\\
+\helpref{wxLogChain}{wxlogchain},\\
+\helpref{wxLogPassThrough}{wxlogpassthrough},\\
+\helpref{wxStreamToTextRedirector}{wxstreamtotextredirector}

 
 This is a general overview of logging classes provided by wxWindows. The word
 logging here has a broad sense, including all of the program output, not only
 
 This is a general overview of logging classes provided by wxWindows. The word
 logging here has a broad sense, including all of the program output, not only


@@ -15,13 +20,15 @@ functions to use with them.
 
 First of all, no knowledge of {\it wxLog} classes is needed to use them. For
 this, you should only know about {\it wxLogXXX()} functions. All of them have
 
 First of all, no knowledge of {\it wxLog} classes is needed to use them. For
 this, you should only know about {\it wxLogXXX()} functions. All of them have

-the same syntax as {\it printf()}, i.e. they take the format string as the
-first argument and a variable number of arguments. Here are all of them:
+the same syntax as {\it printf()} or {\it vprintf()} , i.e. they take the
+format string as the first argument and respectively a variable number of
+arguments or a variable argument list pointer. Here are all of them:

 
 \begin{itemize}\itemsep=0pt
 \item{\bf wxLogFatalError} which is like {\it wxLogError}, but also
 
 \begin{itemize}\itemsep=0pt
 \item{\bf wxLogFatalError} which is like {\it wxLogError}, but also

-terminates the program with the exit code 3 (using {\it abort()} standard
-function also terminates the program with this exit code).
+terminates the program with the exit code $3$ (using {\it abort()} standard
+function). Unlike for all the other logging functions, this function can't be
+overridden by a log target.

 \item{\bf wxLogError} is the function to use for error messages, i.e. the
 messages that must be shown to the user. The default processing is to pop up a
 message box to inform the user about it.
 \item{\bf wxLogError} is the function to use for error messages, i.e. the
 messages that must be shown to the user. The default processing is to pop up a
 message box to inform the user about it.


@@ -32,7 +39,7 @@ 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.
 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.

-\item{\bf wxLogVerbose} is for verbose output. Normally, it's suppressed, but
+\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}).
 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}).


@@ -41,12 +48,15 @@ bar of the active or specified (as the first argument) \helpref{wxFrame}{wxframe
 \item{\bf wxLogSysError} is mostly used by wxWindows 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
 \item{\bf wxLogSysError} is mostly used by wxWindows 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 the corresponding error
-message. The second form of this function takes the error code explitly as the
-first argument.
+code ({\it errno} or {\it ::GetLastError()} depending on the platform) and
+the corresponding error message. The second form of this function takes the
+error code explicitly as the first argument.

 \item{\bf wxLogDebug} is {\bf the} right function for debug output. It only
 does anything at all in the debug mode (when the preprocessor symbol
 \_\_WXDEBUG\_\_ is defined) and expands to nothing in release mode (otherwise).
 \item{\bf wxLogDebug} is {\bf the} right function for debug output. It only
 does anything at all in the debug mode (when the preprocessor symbol
 \_\_WXDEBUG\_\_ is defined) and expands to nothing in release mode (otherwise).

+{\bf Tip:} under Windows, you must either run the program under debugger or
+use a 3rd party program such as \urlref{DbgView}{http://www.sysinternals.com} 
+to actually see the debug output.

 \item{\bf wxLogTrace} as {\bf wxLogDebug} only does something in debug
 build. The reason for making it a separate function from it is that usually
 there are a lot of trace messages, so it might make sense to separate them
 \item{\bf wxLogTrace} as {\bf wxLogDebug} only does something in debug
 build. The reason for making it a separate function from it is that usually
 there are a lot of trace messages, so it might make sense to separate them


@@ -62,12 +72,26 @@ generic mechanisms, but are not really adapted for wxWindows, while the log
 classes are. Some of advantages in using wxWindows log functions are:
 
 \begin{itemize}\itemsep=0pt
 classes are. Some of advantages in using wxWindows log functions are:
 
 \begin{itemize}\itemsep=0pt

-\item{\bf Portability} It's a common practice to use {\it printf()} statements or
-cout/cerr C++ streams for writing out some (debug or otherwise) information.
+\item{\bf Portability} It is a common practice to use {\it printf()}
+statements or cout/cerr C++ streams for writing out some (debug or otherwise)
+information.

 Although it works just fine under Unix, these messages go strictly nowhere
 under Windows where the stdout of GUI programs is not assigned to anything.
 Thus, you might view {\it wxLogMessage()} as a simple substitute for {\it
 printf()}.
 Although it works just fine under Unix, these messages go strictly nowhere
 under Windows where the stdout of GUI programs is not assigned to anything.
 Thus, you might view {\it wxLogMessage()} as a simple substitute for {\it
 printf()}.

+
+You can also redirect the {\it wxLogXXX} calls to {\it cout} by just writing:
+{\small
+\begin{verbatim}
+  wxLog *logger=new wxLogStream(&cout);
+  wxLog::SetActiveTarget(logger);
+\end{verbatim}
+}
+
+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
 \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


@@ -89,10 +113,10 @@ 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.
 
 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's just a class deriving
+wxWindows 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
 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()}
+is {\it active} at any moment, this is the one used by {\it wxLogXXX()}

 functions. The normal usage of a log object (i.e. object of a class derived
 from wxLog) is to install it as the active target with a call to {\it
 SetActiveTarget()} and it will be used automatically by all subsequent calls
 functions. The normal usage of a log object (i.e. object of a class derived
 from wxLog) is to install it as the active target with a call to {\it
 SetActiveTarget()} and it will be used automatically by all subsequent calls


@@ -116,7 +140,7 @@ 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 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

-applications (it's used by default if you don't do anything) and provides the
+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
 collects all messages generated by the application and also passes them to the
 most reasonable handling of all types of messages for given platform.
 \item{\bf wxLogWindow} This log target provides a "log console" which
 collects all messages generated by the application and also passes them to the


@@ -126,7 +150,7 @@ clear the log, close it completely or save all messages to file.
 anything. The objects of this class may be instantiated to (temporarily)
 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
 anything. The objects of this class may be instantiated to (temporarily)
 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's unwanted, just use this construction:
+reasons it is unwanted, just use this construction:

 
 {\small
 \begin{verbatim}
 
 {\small
 \begin{verbatim}


@@ -144,3 +168,8 @@ reasons it's unwanted, just use this construction:
 }
 \end{itemize}
 
 }
 \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.
+