QMessageLogger Class Reference

\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(QDeclarativeComponent::Status status) {
        if (status == QDeclarativeComponent::Error) {
            foreach (const QDeclarativeError &error, 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 67 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 71 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 72 of file qlogging.h.

References function.

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.

Definition at line 74 of file qlogging.h.

References function.

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 833 of file qlogging.cpp.

References QtCriticalMsg.

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 764 of file qlogging.cpp.

References isFatal(), qt_message(), qt_message_fatal(), and QtCriticalMsg.

Referenced by dumpwarning(), QV4::ConsoleObject::method_assert(), and QQmlPrivate::AOTCompiledContext::writeToConsole().

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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 847 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isCriticalEnabled(), and QtCriticalMsg.

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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 782 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isCriticalEnabled(), isFatal(), qt_message(), qt_message_fatal(), and QtCriticalMsg.

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debug() [1/6]

QDebug QMessageLogger::debug

(

)

const

Logs a debug message using a QDebug stream.

See also

qDebug(), QDebug

Definition at line 489 of file qlogging.cpp.

References QtDebugMsg.

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 385 of file qlogging.cpp.

References isFatal(), qt_message(), qt_message_fatal(), and QtDebugMsg.

Referenced by dumpwarning(), QV4::ConsoleObject::method_count(), QV4::ConsoleObject::method_profile(), QV4::ConsoleObject::method_profileEnd(), QV4::ConsoleObject::method_trace(), statusChanged(), and QQmlPrivate::AOTCompiledContext::writeToConsole().

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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 503 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isDebugEnabled(), and QtDebugMsg.

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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 437 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isDebugEnabled(), isFatal(), qt_message(), qt_message_fatal(), and QtDebugMsg.

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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 950 of file qlogging.cpp.

References QtFatalMsg.

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 930 of file qlogging.cpp.

References qt_message(), qt_message_fatal(), QT_TERMINATE_ON_EXCEPTION, and QtFatalMsg.

Referenced by qt_assert_x().

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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 964 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), and QtFatalMsg.

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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 882 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), qt_message(), qt_message_fatal(), QT_TERMINATE_ON_EXCEPTION, QtCriticalMsg, and QtFatalMsg.

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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 601 of file qlogging.cpp.

References QtInfoMsg.

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 615 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isInfoEnabled(), and QtInfoMsg.

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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 548 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), isFatal(), QLoggingCategory::isInfoEnabled(), qt_message(), qt_message_fatal(), and QtInfoMsg.

Referenced by dumpwarning(), and QQmlPrivate::AOTCompiledContext::writeToConsole().

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noDebug() [1/2]

QNoDebug QMessageLogger::noDebug ( ) const

noexcept

Returns a QNoDebug object, which is used to ignore debugging output.

See also

QNoDebug, qDebug()

Definition at line 534 of file qlogging.cpp.

noDebug() [2/2]

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 717 of file qlogging.cpp.

References QtWarningMsg.

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 648 of file qlogging.cpp.

References isFatal(), qt_message(), qt_message_fatal(), and QtWarningMsg.

Referenced by dumpwarning(), QV4::QObjectSlotDispatcher::impl(), QV4::ConsoleObject::method_profile(), QV4::ConsoleObject::method_profileEnd(), QQuickView::setContent(), QQuickWidget::setContent(), and QQmlPrivate::AOTCompiledContext::writeToConsole().

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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 730 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), QLoggingCategory::isWarningEnabled(), and QtWarningMsg.

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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 666 of file qlogging.cpp.

References QMessageLogContext::category, QLoggingCategory::categoryName(), isFatal(), QLoggingCategory::isWarningEnabled(), qt_message(), qt_message_fatal(), and QtWarningMsg.

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Member Data Documentation

CategoryFunction

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

Definition at line 88 of file qlogging.h.

---

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

• qtbase/src/corelib/global/qlogging.h
• qtbase/src/corelib/global/qlogging.cpp