#include <wx/log.h>
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 wxLogXXX() functions and you may not even know about its existence.
stderr
when wxUSE_GUI
= 0.If more control over the output format is needed, then the first function must be overridden which allows to construct custom messages depending on the log level or even do completely different things depending on the message severity (for example, throw away all messages except warnings and errors, show warnings on the screen and forward the error messages to the user's (or programmer's) cell phone - maybe depending on whether the timestamp tells us if it is day or night in the current time zone).
There also functions to support message buffering. Why are they needed? 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).
Flush() shows them all and clears the buffer contents. This function doesn't do anything if the buffer is already empty.
See also:
As for the (real) trace messages, their handling depends on the currently enabled trace masks: if AddTraceMask() was called for the mask of the given message, it will be logged, otherwise nothing happens.
For example,
wxLogTrace( wxTRACE_OleCalls, "IFoo::Bar() called" );
will log the message if it was preceded by:
wxLog::AddTraceMask( wxTRACE_OleCalls);
The standard trace masks are given in wxLogTrace() documentation.
Finally, the 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 % specifications fully described in the documentation of the standard 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 or calling the shortcut wxLog::DisableTimestamp(), disables timestamping of the messages completely.
See also
Get/Set methods are used to install/query the current active target and, finally, 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.
See also:
Public Member Functions | |
virtual void | Flush () |
Shows all the messages currently in buffer and clears it. | |
void | Log (wxLogLevel level, const wxString &msg, time_t timestamp) |
Log the given message. | |
Static Public Member Functions | |
static void | AddTraceMask (const wxString &mask) |
Add the mask to the list of allowed masks for wxLogTrace(). | |
static void | ClearTraceMasks () |
Removes all trace masks previously set with AddTraceMask(). | |
static void | DontCreateOnDemand () |
Instructs wxLog to not create new log targets on the fly if there is none currently. | |
static void | FlushActive () |
Flushes the current log target if any, does nothing if there is none. | |
static wxLog * | GetActiveTarget () |
Returns the pointer to the active log target (may be NULL). | |
static wxLogLevel | GetLogLevel () |
Returns the current log level limit. | |
static bool | GetRepetitionCounting () |
Returns whether the repetition counting mode is enabled. | |
static const wxString & | GetTimestamp () |
Returns the current timestamp format string. | |
static wxTraceMask | GetTraceMask () |
static const wxArrayString & | GetTraceMasks () |
Returns the currently allowed list of string trace masks. | |
static bool | GetVerbose () |
Returns whether the verbose mode is currently active. | |
static bool | IsAllowedTraceMask (const wxString &mask) |
Returns true if the mask is one of allowed masks for wxLogTrace(). | |
static void | OnLog (wxLogLevel level, const wxString &msg, time_t t) |
Forwards the message at specified level to the DoLog() function of the active log target if there is any, does nothing otherwise. | |
static void | RemoveTraceMask (const wxString &mask) |
Remove the mask from the list of allowed masks for wxLogTrace(). | |
static void | Resume () |
Resumes logging previously suspended by a call to Suspend(). | |
static wxLog * | SetActiveTarget (wxLog *logtarget) |
Sets the specified log target as the active one. | |
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. | |
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. | |
static void | SetTimestamp (const wxString &format) |
Sets the timestamp format prepended by the default log targets to all messages. | |
static void | DisableTimestamp () |
Disables time stamping of the log messages. | |
static void | SetTraceMask (wxTraceMask mask) |
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. | |
static void | Suspend () |
Suspends the logging until Resume() is called. | |
Protected Member Functions | |
virtual void | DoLog (wxLogLevel level, const wxString &msg, time_t timestamp) |
Called to process the message of the specified severity. | |
virtual void | DoLogString (const wxString &msg, time_t timestamp) |
Called to log the specified string. |
static void wxLog::AddTraceMask | ( | const wxString & | mask | ) | [static] |
Add the mask to the list of allowed masks for wxLogTrace().
static void wxLog::ClearTraceMasks | ( | ) | [static] |
static void wxLog::DisableTimestamp | ( | ) | [static] |
Disables time stamping of the log messages.
virtual void wxLog::DoLog | ( | wxLogLevel | level, | |
const wxString & | msg, | |||
time_t | timestamp | |||
) | [protected, virtual] |
Called to process the message of the specified severity.
msg is the text of the message as specified in the call of wxLogXXX() function which generated it and timestamp is the moment when the message was generated.
The base class version prepends the timestamp to the message, adds a prefix corresponding to the log level and then calls DoLogString() with the resulting string.
virtual void wxLog::DoLogString | ( | const wxString & | msg, | |
time_t | timestamp | |||
) | [protected, virtual] |
Called to log the specified string.
The timestamp is already included in the string but still passed to this function.
A simple implementation may just send the string to stdout
or, better, stderr
.
static void wxLog::DontCreateOnDemand | ( | ) | [static] |
Instructs wxLog to not create new log targets on the fly if there is none currently.
(Almost) for internal use only: it is supposed to be called by the application shutdown code.
Note that this function also calls ClearTraceMasks().
virtual void wxLog::Flush | ( | ) | [virtual] |
Shows all the messages currently in buffer and clears it.
If the buffer is already empty, nothing happens.
Reimplemented in wxLogGui, and wxLogBuffer.
static void wxLog::FlushActive | ( | ) | [static] |
static wxLog* wxLog::GetActiveTarget | ( | ) | [static] |
Returns the pointer to the active log target (may be NULL).
static wxLogLevel wxLog::GetLogLevel | ( | ) | [static] |
Returns the current log level limit.
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.
static wxTraceMask wxLog::GetTraceMask | ( | ) | [static] |
static const wxArrayString& wxLog::GetTraceMasks | ( | ) | [static] |
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()
void wxLog::Log | ( | wxLogLevel | level, | |
const wxString & | msg, | |||
time_t | timestamp | |||
) |
Log the given message.
This function should only be called from the DoLog() implementations in the derived classes (which can't call wxLog::DoLog() directly as it is protected), 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:
void wxLogChain::DoLog(wxLogLevel level, const wxString& msg, time_t t) { // let the previous logger show it if ( m_logOld && IsPassingMessages() ) m_logOld->Log(level, msg, t); // and also send it to the new one if ( m_logNew && m_logNew != this ) m_logNew->Log(level, msg, t); }
static void wxLog::OnLog | ( | wxLogLevel | level, | |
const wxString & | msg, | |||
time_t | t | |||
) | [static] |
Forwards the message at specified level to the DoLog() function of the active log target if there is any, does nothing otherwise.
static void wxLog::RemoveTraceMask | ( | const wxString & | mask | ) | [static] |
static void wxLog::Resume | ( | ) | [static] |
Resumes logging previously suspended by a call to Suspend().
All messages logged in the meanwhile will be flushed soon.
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.
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.
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 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 specificators, see strftime() manual for details. Passing an empty string to this function disables message time stamping.
static void wxLog::SetTraceMask | ( | wxTraceMask | mask | ) | [static] |
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.
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 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).
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