QDebug 類

QDebug 類為調試信息提供輸齣流。更多...

頭：	#include <QDebug>
qmake:	QT += core

所有成員列錶，包括繼承成員

公共類型

enum	VerbosityLevel { MinimumVerbosity, DefaultVerbosity, MaximumVerbosity }

公共函數

	QDebug (const QDebug & o )
	QDebug (QtMsgType t )
	QDebug (QString * string )
	QDebug (QIODevice * device )
QDebug &	operator= (const QDebug & other )
	~QDebug ()
bool	autoInsertSpaces () const
QDebug &	maybeQuote (char c = '"')
QDebug &	maybeSpace ()
QDebug &	noquote ()
QDebug &	nospace ()
QDebug &	quote ()
QDebug &	resetFormat ()
void	setAutoInsertSpaces (bool b )
void	setVerbosity (int verbosityLevel )
QDebug &	space ()
void	swap (QDebug & other )
QDebug &	verbosity (int verbosityLevel )
int	verbosity () const
QDebug &	operator<< (QChar t )
QDebug &	operator<< (bool t )
QDebug &	operator<< (char t )
QDebug &	operator<< (short t )
QDebug &	operator<< (unsigned short t )
QDebug &	operator<< (char16_t t )
QDebug &	operator<< (char32_t t )
QDebug &	operator<< (int t )
QDebug &	operator<< (unsigned int t )
QDebug &	operator<< (long t )
QDebug &	operator<< (unsigned long t )
QDebug &	operator<< (qint64 t )
QDebug &	operator<< (quint64 t )
QDebug &	operator<< (float t )
QDebug &	operator<< (double t )
QDebug &	operator<< (const char * t )
QDebug &	operator<< (const QString & t )
QDebug &	operator<< (const QStringRef & t )
QDebug &	operator<< (QStringView s )
QDebug &	operator<< (QLatin1String t )
QDebug &	operator<< (const QByteArray & t )
QDebug &	operator<< (const void * t )

QDebug	operator<< (QDebug debug , const QFlags<T> & flags )
QDebug	operator<< (QDebug debug , const QList<T> & list )
QDebug	operator<< (QDebug debug , const QVector<T> & vec )
QDebug	operator<< (QDebug debug , const std::vector<T, Alloc> & vec )
QDebug	operator<< (QDebug debug , const std::list<T, Alloc> & vec )
QDebug	operator<< (QDebug debug , const std::map<Key, T, Compare, Alloc> & map )
QDebug	operator<< (QDebug debug , const std::multimap<Key, T, Compare, Alloc> & map )
QDebug	operator<< (QDebug debug , const QMap<Key, T> & map )
QDebug	operator<< (QDebug debug , const QHash<Key, T> & hash )
QDebug	operator<< (QDebug debug , const QPair<T1, T2> & pair )
QDebug	operator<< (QDebug debug , const QSet<T> & set )

詳細描述

就會使用 QDebug，每當開發者需要把調試 (或跟蹤) 信息寫入輸齣到設備、文件、字符串或控製颱時。

基本用法

In the common case, it is useful to call the qDebug () function to obtain a default QDebug object to use for writing debugging information.

    qDebug() << "Date:" << QDate::currentDate();
    qDebug() << "Types:" << QString("String") << QChar('x') << QRect(0, 10, 50, 40);
    qDebug() << "Custom coordinate type:" << coordinate;

This constructs a QDebug object using the constructor that accepts a QtMsgType value of QtDebugMsg 。同樣， qWarning (), qCritical () 和 qFatal () functions also return QDebug objects for the corresponding message types.

The class also provides several constructors for other situations, including a constructor that accepts a QFile 或任何其它 QIODevice subclass that is used to write debugging information to files and other devices. The constructor that accepts a QString is used to write to a string for display or serialization.

格式化選項

QDebug formats output so that it's easily readable. It automatically adds spaces between arguments, and adds quotes around QString , QByteArray , QChar 自變量。

可以微調這些選項透過 space (), nospace () 和 quote (), noquote () 方法。此外， QTextStream 操作符可以管道到 QDebug 流。

QDebugStateSaver limits changes to the formatting to the current scope. resetFormat () resets the options to the default ones.

把自定義類型寫入流

Many standard types can be written to QDebug objects, and Qt provides support for most Qt value types. To add support for custom types, you need to implement a streaming operator, as in the following example:

QDebug operator<<(QDebug debug, const Coordinate &c)
{
    QDebugStateSaver saver(debug);
    debug.nospace() << '(' << c.x() << ", " << c.y() << ')';
    return debug;
}

This is described in the 調試技術 and 創建自定義 Qt 類型 documents.

成員類型文檔編製

enum QDebug:: VerbosityLevel

此枚舉描述冗餘級彆的範圍。

常量	值
`QDebug::MinimumVerbosity`	`0`
`QDebug::DefaultVerbosity`	`2`
`QDebug::MaximumVerbosity`	`7`

該枚舉在 Qt 5.13 引入或被修改。

另請參閱 verbosity () 和 setVerbosity ().

成員函數文檔編製

QDebug:: QDebug (const QDebug & o )

Constructs a copy of the other debug stream o .

QDebug:: QDebug ( QtMsgType t )

Constructs a debug stream that writes to the handler for the message type t .

QDebug:: QDebug ( QString * string )

Constructs a debug stream that writes to the given string .

QDebug:: QDebug ( QIODevice * device )

Constructs a debug stream that writes to the given device .

QDebug &QDebug:: operator= (const QDebug & other )

賦值 other debug stream to this stream and returns a reference to this stream.

QDebug:: ~QDebug ()

Flushes any pending data to be written and destroys the debug stream.

bool QDebug:: autoInsertSpaces () const

返迴 true 若此 QDebug instance will automatically insert spaces between writes.

該函數在 Qt 5.0 引入。

另請參閱 setAutoInsertSpaces () 和 QDebugStateSaver .

QDebug &QDebug:: maybeQuote ( char c = '"')

Writes a character c to the debug stream, depending on the current setting for automatic insertion of quotes, and returns a reference to the stream.

默認字符是雙引號 " .

該函數在 Qt 5.4 引入。

另請參閱 quote () 和 noquote ().

QDebug &QDebug:: maybeSpace ()

Writes a space character to the debug stream, depending on the current setting for automatic insertion of spaces, and returns a reference to the stream.

另請參閱 space () 和 nospace ().

QDebug &QDebug:: noquote ()

Disables automatic insertion of quotation characters around QChar , QString and QByteArray contents and returns a reference to the stream.

When quoting is disabled, these types are printed without quotation characters and without escaping of non-printable characters.

該函數在 Qt 5.4 引入。

另請參閱 quote () 和 maybeQuote ().

QDebug &QDebug:: nospace ()

Disables automatic insertion of spaces and returns a reference to the stream.

另請參閱 space () 和 maybeSpace ().

QDebug &QDebug:: quote ()

Enables automatic insertion of quotation characters around QChar , QString and QByteArray contents and returns a reference to the stream.

Quoting is enabled by default.

該函數在 Qt 5.4 引入。

另請參閱 noquote () 和 maybeQuote ().

QDebug &QDebug:: resetFormat ()

Resets the stream formatting options, bringing it back to its original constructed state.

該函數在 Qt 5.4 引入。

另請參閱 space () 和 quote ().

void QDebug:: setAutoInsertSpaces ( bool b )

Enables automatic insertion of spaces between writes if b is true; otherwise automatic insertion of spaces is disabled.

該函數在 Qt 5.0 引入。

另請參閱 autoInsertSpaces () 和 QDebugStateSaver .

void QDebug:: setVerbosity ( int verbosityLevel )

Sets the verbosity of the stream to verbosityLevel .

允許範圍是從 0 到 7。默認值為 2。

該函數在 Qt 5.6 引入。

另請參閱 verbosity () 和 VerbosityLevel .

QDebug &QDebug:: space ()

Writes a space character to the debug stream and returns a reference to the stream.

The stream remembers that automatic insertion of spaces is enabled for future writes.

另請參閱 nospace () 和 maybeSpace ().

void QDebug:: swap ( QDebug & other )

Swaps this debug stream instance with other 。此函數非常快且從不失敗。

該函數在 Qt 5.0 引入。

QDebug &QDebug:: verbosity ( int verbosityLevel )

Sets the verbosity of the stream to verbosityLevel 並返迴流引用。

允許範圍是從 0 到 7。默認值為 2。

該函數在 Qt 5.13 引入。

另請參閱 verbosity (), setVerbosity ()，和 VerbosityLevel .

int QDebug:: verbosity () const

返迴調試流的冗餘。

Streaming operators can check the value to decide whether verbose output is desired and print more information depending on the level. Higher values indicate that more information is desired.

允許範圍是從 0 到 7。默認值為 2。

該函數在 Qt 5.6 引入。

另請參閱 setVerbosity () 和 VerbosityLevel .

QDebug &QDebug:: operator<< ( QChar t )

Writes the character, t , to the stream and returns a reference to the stream. Normally, QDebug prints control characters and non-US-ASCII characters as their C escape sequences or their Unicode value (\u1234). To print non-printable characters without transformation, enable the noquote () functionality, but note that some QDebug backends may not be 8-bit clean and may not be able to represent t .

QDebug &QDebug:: operator<< ( bool t )

Writes the boolean value, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( char t )

Writes the character, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( short t )

Writes the signed short integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( unsigned short t )

Writes then unsigned short integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( char16_t t )

Writes the UTF-16 character, t ，到流並返迴流引用。

該函數在 Qt 5.5 引入。

QDebug &QDebug:: operator<< ( char32_t t )

Writes the UTF-32 character, t ，到流並返迴流引用。

該函數在 Qt 5.5 引入。

QDebug &QDebug:: operator<< ( int t )

Writes the signed integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( unsigned int t )

Writes then unsigned integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( long t )

Writes the signed long integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( unsigned long t )

Writes then unsigned long integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( qint64 t )

Writes the signed 64-bit integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( quint64 t )

Writes then unsigned 64-bit integer, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( float t )

Writes the 32-bit floating point number, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< ( double t )

Writes the 64-bit floating point number, t ，到流並返迴流引用。

QDebug &QDebug:: operator<< (const char * t )

Writes the '\0'-terminated string, t , to the stream and returns a reference to the stream. The string is never quoted nor transformed to the output, but note that some QDebug backends might not be 8-bit clean.

QDebug &QDebug:: operator<< (const QString & t )

寫入字符串 t , to the stream and returns a reference to the stream. Normally, QDebug prints the string inside quotes and transforms non-printable characters to their Unicode values (\u1234).