\inmodule QtCore More...

#include <qlogging.h>

Collaboration diagram for QMessageLogger:

Public Member Functions
constexpr	QMessageLogger ()
	Constructs a default QMessageLogger.
constexpr	QMessageLogger (const char file, int line, const char function)
	Constructs a QMessageLogger to record log messages for file at line in function.
constexpr	QMessageLogger (const char file, int line, const char function, const char *category)
	Constructs a QMessageLogger to record category messages for file at line in function.
void	debug (const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(2
	Logs a debug message specified with format msg.
void void	noDebug (const char *,...) const Q_ATTRIBUTE_FORMAT_PRINTF(2
void void Q_DECL_COLD_FUNCTION void	warning (const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(2
	Logs a warning message specified with format msg.
void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void	critical (const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(2
	Logs a critical message specified with format msg.
void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void	fatal (const char *msg,...) const noexcept Q_ATTRIBUTE_FORMAT_PRINTF(2
	Logs a fatal message specified with format msg.
void	debug (const QLoggingCategory &cat, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
	Logs a debug message specified with format msg for the context cat.
void void	debug (CategoryFunction catFunc, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
void void void	info (const QLoggingCategory &cat, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
	Logs an informational message specified with format msg for the context cat.
void void void void	info (CategoryFunction catFunc, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
void void void void Q_DECL_COLD_FUNCTION void	warning (const QLoggingCategory &cat, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
	Logs a warning message specified with format msg for the context cat.
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void	warning (CategoryFunction catFunc, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void	critical (const QLoggingCategory &cat, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
	Logs a critical message specified with format msg for the context cat.
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void	critical (CategoryFunction catFunc, const char *msg,...) const Q_ATTRIBUTE_FORMAT_PRINTF(3
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void	fatal (const QLoggingCategory &cat, const char *msg,...) const noexcept Q_ATTRIBUTE_FORMAT_PRINTF(3
	Logs a fatal message specified with format msg for the context cat.
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void	fatal (CategoryFunction catFunc, const char *msg,...) const noexcept Q_ATTRIBUTE_FORMAT_PRINTF(3
void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void QDebug	debug () const
	Logs a debug message using a QDebug stream.
QDebug	debug (const QLoggingCategory &cat) const
	Logs a debug message into category cat using a QDebug stream.
QDebug	debug (CategoryFunction catFunc) const
QDebug	info () const
	Logs an informational message using a QDebug stream.
QDebug	info (const QLoggingCategory &cat) const
	Logs an informational message into the category cat using a QDebug stream.
QDebug	info (CategoryFunction catFunc) const
Q_DECL_COLD_FUNCTION QDebug	warning () const
	Logs a warning message using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	warning (const QLoggingCategory &cat) const
	Logs a warning message into category cat using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	warning (CategoryFunction catFunc) const
Q_DECL_COLD_FUNCTION QDebug	critical () const
	Logs a critical message using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	critical (const QLoggingCategory &cat) const
	Logs a critical message into category cat using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	critical (CategoryFunction catFunc) const
Q_DECL_COLD_FUNCTION QDebug	fatal () const
	Logs a fatal message using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	fatal (const QLoggingCategory &cat) const
	Logs a fatal message into category cat using a QDebug stream.
Q_DECL_COLD_FUNCTION QDebug	fatal (CategoryFunction catFunc) const
QNoDebug	noDebug (...) const noexcept

Public Attributes
void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void typedef const QLoggingCategory &(*	CategoryFunction )()
	This is a typedef for a pointer to a function with the following signature:

Detailed Description

\inmodule QtCore

The QMessageLogger class generates log messages.

Since: 5.0

QMessageLogger is used to generate messages for the Qt logging framework. Usually one uses it through qDebug(), qInfo(), qWarning(), qCritical, or qFatal() functions, which are actually macros: For example qDebug() expands to QMessageLogger(FILE, LINE, Q_FUNC_INFO).debug() for debug builds, and QMessageLogger(0, 0, 0).debug() for release builds.

One example of direct use is to forward errors that stem from a scripting language, e.g. QML:

    void statusChanged(QQmlComponent::Status status) {
        if (status == QQmlComponent::Error) {
            for (const QQmlError &error: std::as_const(component->errors())) {
                const QByteArray file = error.url().toEncoded();
                QMessageLogger(file.constData(), error.line(), 0).debug() << error.description();
            }
        }
    }

See also: QMessageLogContext, qDebug(), qInfo(), qWarning(), qCritical(), qFatal()

Definition at line 73 of file qlogging.h.

Constructor & Destructor Documentation

◆ QMessageLogger() [1/3]

QMessageLogger::QMessageLogger ( )

inlineconstexpr

Constructs a default QMessageLogger.

See the other constructors to specify context information.

Definition at line 77 of file qlogging.h.

◆ QMessageLogger() [2/3]

QMessageLogger::QMessageLogger	(	const char *	file,
		int	line,
		const char *	function )

inlineconstexpr

Constructs a QMessageLogger to record log messages for file at line in function.

The is equivalent to QMessageLogger(file, line, function, "default")

Definition at line 78 of file qlogging.h.

◆ QMessageLogger() [3/3]

QMessageLogger::QMessageLogger	(	const char *	file,
		int	line,
		const char *	function,
		const char *	category )

inlineconstexpr

Constructs a QMessageLogger to record category messages for file at line in function.

See also: QLoggingCategory

Definition at line 80 of file qlogging.h.

Member Function Documentation

◆ critical() [1/6]

QDebug QMessageLogger::critical ( ) const

Logs a critical message using a QDebug stream.

See also: qCritical(), QDebug

Definition at line 814 of file qlogging.cpp.

◆ critical() [2/6]

Q_DECL_COLD_FUNCTION QDebug QMessageLogger::critical ( CategoryFunction catFunc ) const

◆ critical() [3/6]

void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QMessageLogger::critical	(	CategoryFunction	catFunc,
		const char *	msg,
			... ) const

◆ critical() [4/6]

void QMessageLogger::critical	(	const char *	msg,
			... ) const

Logs a critical message specified with format msg.

Additional parameters, specified by msg, may be used.

See also: qCritical()

Definition at line 757 of file qlogging.cpp.

◆ critical() [5/6]

QDebug QMessageLogger::critical ( const QLoggingCategory & cat ) const

Logs a critical message into category cat using a QDebug stream.

Since: 5.3

See also: qCCritical(), QDebug

Definition at line 828 of file qlogging.cpp.

◆ critical() [6/6]

void QMessageLogger::critical	(	const QLoggingCategory &	cat,
		const char *	msg,
			... ) const

Logs a critical message specified with format msg for the context cat.

Additional parameters, specified by msg, may be used.

Since: 5.3

See also: qCCritical()

Definition at line 773 of file qlogging.cpp.

◆ debug() [1/6]

QDebug QMessageLogger::debug ( ) const

Logs a debug message using a QDebug stream.

See also: qDebug(), QDebug

Definition at line 520 of file qlogging.cpp.

◆ debug() [2/6]

QDebug QMessageLogger::debug ( CategoryFunction catFunc ) const

◆ debug() [3/6]

void void QMessageLogger::debug	(	CategoryFunction	catFunc,
		const char *	msg,
			... ) const

◆ debug() [4/6]

void QMessageLogger::debug	(	const char *	msg,
			... ) const

Logs a debug message specified with format msg.

Additional parameters, specified by msg, may be used.

See also: qDebug()

Definition at line 430 of file qlogging.cpp.

◆ debug() [5/6]

QDebug QMessageLogger::debug ( const QLoggingCategory & cat ) const

Logs a debug message into category cat using a QDebug stream.

Since: 5.3

See also: qCDebug(), QDebug

Definition at line 534 of file qlogging.cpp.

◆ debug() [6/6]

void QMessageLogger::debug	(	const QLoggingCategory &	cat,
		const char *	msg,
			... ) const

Logs a debug message specified with format msg for the context cat.

Additional parameters, specified by msg, may be used.

Since: 5.3

See also: qCDebug()

Definition at line 478 of file qlogging.cpp.

◆ fatal() [1/6]

QDebug QMessageLogger::fatal ( ) const

Logs a fatal message using a QDebug stream.

Since: 6.5

See also: qFatal(), QDebug

Definition at line 926 of file qlogging.cpp.

◆ fatal() [2/6]

Q_DECL_COLD_FUNCTION QDebug QMessageLogger::fatal ( CategoryFunction catFunc ) const

◆ fatal() [3/6]

void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void QMessageLogger::fatal	(	CategoryFunction	catFunc,
		const char *	msg,
			... ) const

noexcept

◆ fatal() [4/6]

void QMessageLogger::fatal	(	const char *	msg,
			... ) const

noexcept

Logs a fatal message specified with format msg.

Additional parameters, specified by msg, may be used.

See also: qFatal()

Definition at line 905 of file qlogging.cpp.

◆ fatal() [5/6]

QDebug QMessageLogger::fatal ( const QLoggingCategory & cat ) const

Logs a fatal message into category cat using a QDebug stream.

Since: 6.5

See also: qCFatal(), QDebug

Definition at line 940 of file qlogging.cpp.

◆ fatal() [6/6]

void QMessageLogger::fatal	(	const QLoggingCategory &	cat,
		const char *	msg,
			... ) const

noexcept

Logs a fatal message specified with format msg for the context cat.

Additional parameters, specified by msg, may be used.

Since: 6.5

See also: qCFatal()

Definition at line 861 of file qlogging.cpp.

◆ info() [1/5]

QDebug QMessageLogger::info ( ) const

Logs an informational message using a QDebug stream.

Since: 5.5

See also: qInfo(), QDebug

Definition at line 609 of file qlogging.cpp.

◆ info() [2/5]

QDebug QMessageLogger::info ( CategoryFunction catFunc ) const

◆ info() [3/5]

void void void void QMessageLogger::info	(	CategoryFunction	catFunc,
		const char *	msg,
			... ) const

◆ info() [4/5]

QDebug QMessageLogger::info ( const QLoggingCategory & cat ) const

Logs an informational message into the category cat using a QDebug stream.

Since: 5.5

See also: qCInfo(), QDebug

Definition at line 623 of file qlogging.cpp.

◆ info() [5/5]

void QMessageLogger::info	(	const QLoggingCategory &	cat,
		const char *	msg,
			... ) const

Logs an informational message specified with format msg for the context cat.

Additional parameters, specified by msg, may be used.

Since: 5.5

See also: qCInfo()

Definition at line 566 of file qlogging.cpp.

◆ noDebug() [1/2]

QNoDebug QMessageLogger::noDebug ( ... ) const

inlinenoexcept

◆ noDebug() [2/2]

void void QMessageLogger::noDebug	(	const char *	,
			... ) const

Ignores logging output

See also: QNoDebug, qDebug()

◆ warning() [1/6]

QDebug QMessageLogger::warning ( ) const

Logs a warning message using a QDebug stream.

See also: qWarning(), QDebug

Definition at line 712 of file qlogging.cpp.

◆ warning() [2/6]

Q_DECL_COLD_FUNCTION QDebug QMessageLogger::warning ( CategoryFunction catFunc ) const

◆ warning() [3/6]

void void void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QMessageLogger::warning	(	CategoryFunction	catFunc,
		const char *	msg,
			... ) const

◆ warning() [4/6]

void QMessageLogger::warning	(	const char *	msg,
			... ) const

Logs a warning message specified with format msg.

Additional parameters, specified by msg, may be used.

See also: qWarning()

Definition at line 655 of file qlogging.cpp.

◆ warning() [5/6]

QDebug QMessageLogger::warning ( const QLoggingCategory & cat ) const

Logs a warning message into category cat using a QDebug stream.

See also: qCWarning(), QDebug

Definition at line 725 of file qlogging.cpp.

◆ warning() [6/6]

void QMessageLogger::warning	(	const QLoggingCategory &	cat,
		const char *	msg,
			... ) const

Logs a warning message specified with format msg for the context cat.

Additional parameters, specified by msg, may be used.

Since: 5.3

See also: qCWarning()

Definition at line 671 of file qlogging.cpp.

Member Data Documentation

◆ CategoryFunction

void void Q_DECL_COLD_FUNCTION void Q_DECL_COLD_FUNCTION void QT_MESSAGE_LOGGER_NORETURN Q_DECL_COLD_FUNCTION void typedef const QLoggingCategory &(* QMessageLogger::CategoryFunction) ()

This is a typedef for a pointer to a function with the following signature:

const QLoggingCategory &category();

The Q_DECLARE_LOGGING_CATEGORY macro generates a function declaration with this signature, and Q_LOGGING_CATEGORY generates its definition.

Since: 5.3

See also: QLoggingCategory

Definition at line 94 of file qlogging.h.

The documentation for this class was generated from the following files:

qtbase/src/corelib/global/qlogging.h (bc83d91d4e3575ba688d65e12860c05b3fb1dcbd)
qtbase/src/corelib/global/qlogging.cpp (dc8a6de42c8adb89275628f0adb067e9664a795d)

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ QMessageLogger() [1/3]

◆ QMessageLogger() [2/3]

◆ QMessageLogger() [3/3]

Member Function Documentation

◆ critical() [1/6]

◆ critical() [2/6]

◆ critical() [3/6]

◆ critical() [4/6]

◆ critical() [5/6]

◆ critical() [6/6]

◆ debug() [1/6]

◆ debug() [2/6]

◆ debug() [3/6]

◆ debug() [4/6]

◆ debug() [5/6]

◆ debug() [6/6]

◆ fatal() [1/6]

◆ fatal() [2/6]

◆ fatal() [3/6]

◆ fatal() [4/6]

◆ fatal() [5/6]

◆ fatal() [6/6]

◆ info() [1/5]

◆ info() [2/5]

◆ info() [3/5]

◆ info() [4/5]

◆ info() [5/5]

◆ noDebug() [1/2]

◆ noDebug() [2/2]

◆ warning() [1/6]

◆ warning() [2/6]

◆ warning() [3/6]

◆ warning() [4/6]

◆ warning() [5/6]

◆ warning() [6/6]

Member Data Documentation

◆ CategoryFunction