The QMessageLogger class generates log messages. 更多...
| 头： | #include <QMessageLogger> |
| qmake: | QT += core |
| Since: | Qt 5.0 |
| typedef | CategoryFunction |
| 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 |
| void | critical (const QLoggingCategory & cat , const char * msg , ... ) const |
| void | critical (CategoryFunction catFunc , const char * msg , ... ) const |
| QDebug | critical () const |
| QDebug | critical (const QLoggingCategory & cat ) const |
| QDebug | critical (CategoryFunction catFunc ) const |
| void | debug (const char * msg , ... ) const |
| void | debug (const QLoggingCategory & cat , const char * msg , ... ) const |
| void | debug (CategoryFunction catFunc , const char * msg , ... ) const |
| QDebug | debug () const |
| QDebug | debug (const QLoggingCategory & cat ) const |
| QDebug | debug (CategoryFunction catFunc ) const |
| void | fatal (const char * msg , ... ) const |
| void | info (const char * msg , ... ) const |
| void | info (const QLoggingCategory & cat , const char * msg , ... ) const |
| void | info (CategoryFunction catFunc , const char * msg , ... ) const |
| QDebug | info () const |
| QDebug | info (const QLoggingCategory & cat ) const |
| QDebug | info (CategoryFunction catFunc ) const |
| void | warning (const char * msg , ... ) const |
| void | warning (const QLoggingCategory & cat , const char * msg , ... ) const |
| void | warning (CategoryFunction catFunc , const char * msg , ... ) const |
| QDebug | warning () const |
| QDebug | warning (const QLoggingCategory & cat ) const |
| QDebug | warning (CategoryFunction catFunc ) const |
The QMessageLogger class generates log messages.
QMessageLogger is used to generate messages for the Qt logging framework. Usually one uses it through qDebug (), qInfo (), qWarning (), qCritical ，或 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();
}
}
}
另请参阅 QMessageLogContext , qDebug (), qInfo (), qWarning (), qCritical ()，和 qFatal ().
这是采用以下签名的函数指针的 typedef：
const QLoggingCategory &category();
A function which this signature is generated by Q_DECLARE_LOGGING_CATEGORY , Q_LOGGING_CATEGORY .
This typedef was introduced in Qt 5.3.
Constructs a default QMessageLogger . See the other constructors to specify context information.
构造 QMessageLogger to record log messages for file at line in function . The is equivalent to QMessageLogger (file, line, function, "default")
构造 QMessageLogger to record category messages for file at line in function .
Logs a critical message specified with format msg . Additional parameters, specified by msg , may be used.
另请参阅 qCritical ().
Logs a critical message specified with format msg for the context cat . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCCritical ().
Logs a critical message specified with format msg for the context returned by catFunc . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCCritical ().
Logs a critical message using a QDebug stream
Logs a critical message into category cat 使用 QDebug stream.
该函数在 Qt 5.3 引入。
另请参阅 qCCritical () 和 QDebug .
Logs a critical message into category returned by catFunc 使用 QDebug stream.
该函数在 Qt 5.3 引入。
另请参阅 qCCritical () 和 QDebug .
Logs a debug message specified with format msg . Additional parameters, specified by msg , may be used.
另请参阅 qDebug ().
Logs a debug message specified with format msg for the context cat . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCDebug ().
Logs a debug message specified with format msg for the context returned by catFunc . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCDebug ().
Logs a debug message using a QDebug stream
Logs a debug message into category cat 使用 QDebug stream.
该函数在 Qt 5.3 引入。
Logs a debug message into category returned by catFunc 使用 QDebug stream.
该函数在 Qt 5.3 引入。
Logs a fatal message specified with format msg . Additional parameters, specified by msg , may be used.
另请参阅 qFatal ().
Logs an informational message specified with format msg . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.5 引入。
另请参阅 qInfo ().
Logs an informational message specified with format msg for the context cat . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.5 引入。
另请参阅 qCInfo ().
Logs an informational message specified with format msg for the context returned by catFunc . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.5 引入。
另请参阅 qCInfo ().
Logs an informational message using a QDebug stream.
该函数在 Qt 5.5 引入。
Logs an informational message into the category cat 使用 QDebug stream.
该函数在 Qt 5.5 引入。
Logs an informational message into category returned by catFunc 使用 QDebug stream.
该函数在 Qt 5.5 引入。
Logs a warning message specified with format msg . Additional parameters, specified by msg , may be used.
另请参阅 qWarning ().
Logs a warning message specified with format msg for the context cat . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCWarning ().
Logs a warning message specified with format msg for the context returned by catFunc . Additional parameters, specified by msg , may be used.
该函数在 Qt 5.3 引入。
另请参阅 qCWarning ().
Logs a warning message using a QDebug stream
Logs a warning message into category cat 使用 QDebug stream.
Logs a warning message into category returned by catFunc 使用 QDebug stream.
该函数在 Qt 5.3 引入。