Version: 3.1.1
wxLog Class Reference

#include <wx/log.h>

+ Inheritance diagram for wxLog:

Detailed Description

wxLog class defines the interface for the log targets used by wxWidgets logging functions as explained in the Logging Overview.

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.

Otherwise, it is completely hidden behind the wxLogXXX() functions and you may not even know about its existence.

Note
For console-mode applications, the default target is wxLogStderr, so that all wxLogXXX() functions print on stderr when wxUSE_GUI = 0.

Library:  wxBase
Category:  Logging
See also
Logging Overview, wxLogXXX() functions

Public Member Functions

wxLogFormatterSetFormatter (wxLogFormatter *formatter)
 Sets the specified formatter as the active one. More...
 
virtual void Flush ()
 Show all pending output and clear the buffer. More...
 
void LogRecord (wxLogLevel level, const wxString &msg, const wxLogRecordInfo &info)
 Log the given record. More...
 

Static Public Member Functions

Trace mask functions
static void AddTraceMask (const wxString &mask)
 Add the mask to the list of allowed masks for wxLogTrace(). More...
 
static void ClearTraceMasks ()
 Removes all trace masks previously set with AddTraceMask(). More...
 
static const wxArrayStringGetTraceMasks ()
 Returns the currently allowed list of string trace masks. More...
 
static bool IsAllowedTraceMask (const wxString &mask)
 Returns true if the mask is one of allowed masks for wxLogTrace(). More...
 
static void RemoveTraceMask (const wxString &mask)
 Remove the mask from the list of allowed masks for wxLogTrace(). More...
 
Log target functions
static void DontCreateOnDemand ()
 Instructs wxLog to not create new log targets on the fly if there is none currently (see GetActiveTarget()). More...
 
static wxLogGetActiveTarget ()
 Returns the pointer to the active log target (may be NULL). More...
 
static wxLogSetActiveTarget (wxLog *logtarget)
 Sets the specified log target as the active one. More...
 
static wxLogSetThreadActiveTarget (wxLog *logger)
 Sets a thread-specific log target. More...
 
static void FlushActive ()
 Flushes the current log target if any, does nothing if there is none. More...
 
static void Resume ()
 Resumes logging previously suspended by a call to Suspend(). More...
 
static void Suspend ()
 Suspends the logging until Resume() is called. More...
 
Log level functions
static wxLogLevel GetLogLevel ()
 Returns the current log level limit. More...
 
static bool IsLevelEnabled (wxLogLevel level, wxString component)
 Returns true if logging at this level is enabled for the current thread. More...
 
static void SetComponentLevel (const wxString &component, wxLogLevel level)
 Sets the log level for the given component. More...
 
static void SetLogLevel (wxLogLevel logLevel)
 Specifies that log messages with level greater (numerically) than logLevel should be ignored and not sent to the active log target. More...
 
Enable/disable features functions
static bool EnableLogging (bool enable=true)
 Globally enable or disable logging. More...
 
static bool IsEnabled ()
 Returns true if logging is enabled at all now. More...
 
static bool GetRepetitionCounting ()
 Returns whether the repetition counting mode is enabled. More...
 
static void SetRepetitionCounting (bool repetCounting=true)
 Enables logging mode in which a log message is logged once, and in case exactly the same message successively repeats one or more times, only the number of repetitions is logged. More...
 
static const wxStringGetTimestamp ()
 Returns the current timestamp format string. More...
 
static void SetTimestamp (const wxString &format)
 Sets the timestamp format prepended by the default log targets to all messages. More...
 
static void DisableTimestamp ()
 Disables time stamping of the log messages. More...
 
static bool GetVerbose ()
 Returns whether the verbose mode is currently active. More...
 
static void SetVerbose (bool verbose=true)
 Activates or deactivates verbose mode in which the verbose messages are logged as the normal ones instead of being silently dropped. More...
 

Protected Member Functions

Logging callbacks.

The functions which should be overridden by custom log targets.

When defining a new log target, you have a choice between overriding DoLogRecord(), which provides maximal flexibility, DoLogTextAtLevel() which can be used if you don't intend to change the default log messages formatting but want to handle log messages of different levels differently or, in the simplest case, DoLogText().

virtual void DoLogRecord (wxLogLevel level, const wxString &msg, const wxLogRecordInfo &info)
 Called to log a new record. More...
 
virtual void DoLogTextAtLevel (wxLogLevel level, const wxString &msg)
 Called to log the specified string at given level. More...
 
virtual void DoLogText (const wxString &msg)
 Called to log the specified string. More...
 

Member Function Documentation

static void wxLog::AddTraceMask ( const wxString mask)
static

Add the mask to the list of allowed masks for wxLogTrace().

See also
RemoveTraceMask(), GetTraceMasks()
static void wxLog::ClearTraceMasks ( )
static

Removes all trace masks previously set with AddTraceMask().

See also
RemoveTraceMask()
static void wxLog::DisableTimestamp ( )
static

Disables time stamping of the log messages.

Notice that the current time stamp is only used by the default log formatter and custom formatters may ignore calls to this function.

Since
2.9.0
virtual void wxLog::DoLogRecord ( wxLogLevel  level,
const wxString msg,
const wxLogRecordInfo info 
)
protectedvirtual

Called to log a new record.

Any log message created by wxLogXXX() functions is passed to this method of the active log target. The default implementation prepends the timestamp and, for some log levels (e.g. error and warning), the corresponding prefix to msg and passes it to DoLogTextAtLevel().

You may override this method to implement custom formatting of the log messages or to implement custom filtering of log messages (e.g. you could discard all log messages coming from the given source file).

virtual void wxLog::DoLogText ( const wxString msg)
protectedvirtual

Called to log the specified string.

A simple implementation might just send the string to stdout or stderr or save it in a file (of course, the already existing wxLogStderr can be used for this).

The base class version of this function asserts so it must be overridden if you don't override DoLogRecord() or DoLogTextAtLevel().

virtual void wxLog::DoLogTextAtLevel ( wxLogLevel  level,
const wxString msg 
)
protectedvirtual

Called to log the specified string at given level.

The base class versions logs debug and trace messages on the system default debug output channel and passes all the other messages to DoLogText().

static void wxLog::DontCreateOnDemand ( )
static

Instructs wxLog to not create new log targets on the fly if there is none currently (see GetActiveTarget()).

(Almost) for internal use only: it is supposed to be called by the application shutdown code (where you don't want the log target to be automatically created anymore).

Note that this function also calls ClearTraceMasks().

static bool wxLog::EnableLogging ( bool  enable = true)
static

Globally enable or disable logging.

Calling this function with false argument disables all log messages for the current thread.

See also
wxLogNull, IsEnabled()
Returns
The old state, i.e. true if logging was previously enabled and false if it was disabled.
virtual void wxLog::Flush ( )
virtual

Show all pending output and clear the buffer.

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). This function shows them all and clears the buffer contents. If the buffer is already empty, nothing happens.

If you override this method in a derived class, call the base class version first, before doing anything else.

Reimplemented in wxLogGui, and wxLogBuffer.

static void wxLog::FlushActive ( )
static

Flushes the current log target if any, does nothing if there is none.

When this method is called from the main thread context, it also flushes any previously buffered messages logged by the other threads. When it is called from the other threads it simply calls Flush() on the currently active log target, so it mostly makes sense to do this if a thread has its own logger set with SetThreadActiveTarget().

static wxLog* wxLog::GetActiveTarget ( )
static

Returns the pointer to the active log target (may be NULL).

Notice that if SetActiveTarget() hadn't been previously explicitly called, this function will by default try to create a log target by calling wxAppTraits::CreateLogTarget() which may be overridden in a user-defined traits class to change the default behaviour. You may also call DontCreateOnDemand() to disable this behaviour.

When this function is called from threads other than main one, auto-creation doesn't happen. But if the thread has a thread-specific log target previously set by SetThreadActiveTarget(), it is returned instead of the global one. Otherwise, the global log target is returned.

static wxLogLevel wxLog::GetLogLevel ( )
static

Returns the current log level limit.

All messages at levels strictly greater than the value returned by this function are not logged at all.

See also
SetLogLevel(), IsLevelEnabled()
static bool wxLog::GetRepetitionCounting ( )
static

Returns whether the repetition counting mode is enabled.

static const wxString& wxLog::GetTimestamp ( )
static

Returns the current timestamp format string.

Notice that the current time stamp is only used by the default log formatter and custom formatters may ignore this format.

static const wxArrayString& wxLog::GetTraceMasks ( )
static

Returns the currently allowed list of string trace masks.

See also
AddTraceMask().
static bool wxLog::GetVerbose ( )
static

Returns whether the verbose mode is currently active.

static bool wxLog::IsAllowedTraceMask ( const wxString mask)
static

Returns true if the mask is one of allowed masks for wxLogTrace().

See also: AddTraceMask(), RemoveTraceMask()

static bool wxLog::IsEnabled ( )
static

Returns true if logging is enabled at all now.

See also
IsLevelEnabled(), EnableLogging()
static bool wxLog::IsLevelEnabled ( wxLogLevel  level,
wxString  component 
)
static

Returns true if logging at this level is enabled for the current thread.

This function only returns true if logging is globally enabled and if level is less than or equal to the maximal log level enabled for the given component.

See also
IsEnabled(), SetLogLevel(), GetLogLevel(), SetComponentLevel()
Since
2.9.1
void wxLog::LogRecord ( wxLogLevel  level,
const wxString msg,
const wxLogRecordInfo info 
)

Log the given record.

This function should only be called from the DoLog() implementations in the derived classes if they need to call DoLogRecord() on another log object (they can, of course, just use wxLog::DoLogRecord() call syntax to call it on the object itself). It should not be used for logging new messages which can be only sent to the currently active logger using OnLog() which also checks if the logging (for this level) is enabled while this method just directly calls DoLog().

Example of use of this class from wxLogChain:

const wxString& msg,
const wxLogRecordInfo& info)
{
// let the previous logger show it
if ( m_logOld && IsPassingMessages() )
m_logOld->LogRecord(level, msg, info);
// and also send it to the new one
if ( m_logNew && m_logNew != this )
m_logNew->LogRecord(level, msg, info);
}
Since
2.9.1
static void wxLog::RemoveTraceMask ( const wxString mask)
static

Remove the mask from the list of allowed masks for wxLogTrace().

See also
AddTraceMask()
static void wxLog::Resume ( )
static

Resumes logging previously suspended by a call to Suspend().

All messages logged in the meanwhile will be flushed soon.

static wxLog* wxLog::SetActiveTarget ( wxLog logtarget)
static

Sets the specified log target as the active one.

Returns the pointer to the previous active log target (may be NULL). To suppress logging use a new instance of wxLogNull not NULL. If the active log target is set to NULL a new default log target will be created when logging occurs.

See also
SetThreadActiveTarget()
static void wxLog::SetComponentLevel ( const wxString component,
wxLogLevel  level 
)
static

Sets the log level for the given component.

For example, to disable all but error messages from wxWidgets network classes you may use

SetLogLevel() may be used to set the global log level.

Parameters
componentNon-empty component name, possibly using slashes (/) to separate it into several parts.
levelMaximal level of log messages from this component which will be handled instead of being simply discarded.
Since
2.9.1
wxLogFormatter* wxLog::SetFormatter ( wxLogFormatter formatter)

Sets the specified formatter as the active one.

Parameters
formatterThe new formatter. If NULL, reset to the default formatter.

Returns the pointer to the previous formatter. You must delete it if you don't plan to attach it again to a wxLog object later.

Since
2.9.4
static void wxLog::SetLogLevel ( wxLogLevel  logLevel)
static

Specifies that log messages with level greater (numerically) than logLevel should be ignored and not sent to the active log target.

See also
SetComponentLevel()
static void wxLog::SetRepetitionCounting ( bool  repetCounting = true)
static

Enables logging mode in which a log message is logged once, and in case exactly the same message successively repeats one or more times, only the number of repetitions is logged.

static wxLog* wxLog::SetThreadActiveTarget ( wxLog logger)
static

Sets a thread-specific log target.

The log target passed to this function will be used for all messages logged by the current thread using the usual wxLog functions. This shouldn't be called from the main thread which never uses a thread- specific log target but can be used for the other threads to handle thread logging completely separately; instead of buffering thread log messages in the main thread logger.

Notice that unlike for SetActiveTarget(), wxWidgets does not destroy the thread-specific log targets when the thread terminates so doing this is your responsibility.

This method is only available if wxUSE_THREADS is 1, i.e. wxWidgets was compiled with threads support.

Parameters
loggerThe new thread-specific log target, possibly NULL.
Returns
The previous thread-specific log target, initially NULL.
Since
2.9.1
static void wxLog::SetTimestamp ( const wxString format)
static

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 specifiers, see strftime() manual for details. Passing an empty string to this function disables message time stamping.

Notice that the current time stamp is only used by the default log formatter and custom formatters may ignore this format. You can also define a custom wxLogFormatter to customize the time stamp handling beyond changing its format.

static void wxLog::SetVerbose ( bool  verbose = true)
static

Activates or deactivates verbose mode in which the verbose messages are logged as the normal ones instead of being silently dropped.

The verbose messages are the trace messages which are not disabled in the release mode and are generated by wxLogVerbose().

See also
Logging Overview
static void wxLog::Suspend ( )
static

Suspends the logging until Resume() is called.

Note that the latter must be called the same number of times as the former to undo it, i.e. if you call Suspend() twice you must call Resume() twice as well.

Note that suspending the logging means that the log sink won't be flushed periodically, it doesn't have any effect if the current log target does the logging immediately without waiting for Flush() to be called (the standard GUI log target only shows the log dialog when it is flushed, so Suspend() works as expected with it).

See also
Resume(), wxLogNull