QMessageLogger Class
The QMessageLogger class generates log messages. More...
Header: | #include <QMessageLogger> |
qmake: | QT += core |
Since: | Qt 5.0 |
Public Functions
QMessageLogger() | |
QMessageLogger(const char * file, int line, const char * function) | |
QMessageLogger(const char * file, int line, const char * function, const char * category) | |
void | critical(const char * msg, ...) const |
QDebug | critical() const |
void | debug(const char * msg, ...) const |
QDebug | debug() const |
void | fatal(const char * msg, ...) const |
QDebug | warning() const |
Detailed Description
The QMessageLogger class generates log messages.
QMessageLogger is used to generate messages for the Qt logging framework. Usually one uses it through qDebug(), qWarning(), qCritical, or qFatal() functions, which are actually macros that expand to QMessageLogger(__FILE__, __LINE__, Q_FUNC_INFO).debug() et al.
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(), qWarning(), qCritical(), and qFatal().
Member Function Documentation
QMessageLogger::QMessageLogger()
Constructs a default QMessageLogger. See the other constructors to specify context information.
QMessageLogger::QMessageLogger(const char * file, int line, const char * function)
Constructs a QMessageLogger to record log messages for file at line in function. The is equivalent to QMessageLogger(file, line, function, "default")
QMessageLogger::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 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().
QDebug QMessageLogger::critical() const
Logs a critical message using a QDebug stream
See also qCritical() and QDebug.
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().
QDebug QMessageLogger::debug() const
Logs a debug message using a QDebug stream
void QMessageLogger::fatal(const char * msg, ...) const
Logs a fatal message specified with format msg. Additional parameters, specified by msg, may be used.
See also qFatal().
QDebug QMessageLogger::warning() const
Logs a debug message using a QDebug stream