1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- qdebug.cpp -->
<head>
<title>Qt 4.6: QDebug Class Reference</title>
<link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<a name="//apple_ref/cpp/cl//QDebug" />
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://qt.nokia.com/"><img src="images/qt-logo.png" align="left" border="0" /></a></td>
<td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="functions.html"><font color="#004faf">All Functions</font></a> · <a href="overviews.html"><font color="#004faf">Overviews</font></a></td><td class="searchBar" align="right" valign="center"><form action="http://www.google.com/cse" id="cse-search-box"><div><input type="hidden" name="cx" value="000136343326384750312:dhbxnqlakyu" /><input type="hidden" name="ie" value="UTF-8" /><input type="text" name="q" size="31" /><input type="submit" name="sa" value="Search" /></div></form></td>
</tr></table><h1 class="title">QDebug Class Reference<br /><span class="small-subtitle">[<a href="qtcore.html">QtCore</a> module]</span>
</h1>
<p>The QDebug class provides an output stream for debugging information. <a href="#details">More...</a></p>
<pre> #include <QDebug></pre><ul>
<li><a href="qdebug-members.html">List of all members, including inherited members</a></li>
</ul>
<hr />
<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#QDebugx">QDebug</a></b> ( QIODevice * <i>device</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#QDebug-2">QDebug</a></b> ( QString * <i>string</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#QDebug-3">QDebug</a></b> ( QtMsgType <i>type</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#QDebug-4">QDebug</a></b> ( const QDebug & <i>other</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#dtor.QDebug">~QDebug</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#maybeSpace">maybeSpace</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#nospace">nospace</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#space">space</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt">operator<<</a></b> ( QChar <i>t</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-3">operator<<</a></b> ( bool <i>t</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-4">operator<<</a></b> ( char <i>t</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-5">operator<<</a></b> ( signed short <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-6">operator<<</a></b> ( unsigned short <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-7">operator<<</a></b> ( signed int <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-8">operator<<</a></b> ( unsigned int <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-9">operator<<</a></b> ( signed long <i>l</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-10">operator<<</a></b> ( unsigned long <i>l</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-11">operator<<</a></b> ( qint64 <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-12">operator<<</a></b> ( quint64 <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-13">operator<<</a></b> ( float <i>f</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-14">operator<<</a></b> ( double <i>f</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-15">operator<<</a></b> ( const char * <i>s</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-16">operator<<</a></b> ( const QString & <i>s</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-17">operator<<</a></b> ( const QStringRef & <i>s</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-18">operator<<</a></b> ( const QLatin1String & <i>s</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-19">operator<<</a></b> ( const QByteArray & <i>b</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-lt-lt-20">operator<<</a></b> ( const void * <i>p</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDebug & </td><td class="memItemRight" valign="bottom"><b><a href="qdebug.html#operator-eq">operator=</a></b> ( const QDebug & <i>other</i> )</td></tr>
</table>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QDebug class provides an output stream for debugging information.</p>
<p>QDebug is used whenever the developer needs to write out debugging or tracing information to a device, file, string or console.</p>
<a name="basic-use"></a>
<h3>Basic Use</h3>
<p>In the common case, it is useful to call the <a href="qtglobal.html#qDebug">qDebug</a>() function to obtain a default QDebug object to use for writing debugging information.</p>
<pre> qDebug() << "Date:" << QDate::currentDate();
qDebug() << "Types:" << QString("String") << QChar('x') << QRect(0, 10, 50, 40);
qDebug() << "Custom coordinate type:" << coordinate;</pre>
<p>This constructs a QDebug object using the constructor that accepts a <a href="qtglobal.html#QtMsgType-enum">QtMsgType</a> value of <a href="qtglobal.html#QtMsgType-enum">QtDebugMsg</a>. Similarly, the <a href="qtglobal.html#qWarning">qWarning</a>(), <a href="qtglobal.html#qCritical">qCritical</a>() and <a href="qtglobal.html#qFatal">qFatal</a>() functions also return QDebug objects for the corresponding message types.</p>
<p>The class also provides several constructors for other situations, including a constructor that accepts a <a href="qfile.html">QFile</a> or any other <a href="qiodevice.html">QIODevice</a> subclass that is used to write debugging information to files and other devices. The constructor that accepts a <a href="qstring.html">QString</a> is used to write to a string for display or serialization.</p>
<a name="writing-custom-types-to-a-stream"></a>
<h3>Writing Custom Types to a Stream</h3>
<p>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:</p>
<pre> QDebug operator<<(QDebug dbg, const Coordinate &c)
{
dbg.nospace() << "(" << c.x() << ", " << c.y() << ")";
return dbg.space();
}</pre>
<p>This is described in the <a href="debug.html">Debugging Techniques</a> and <a href="custom-types.html#making-the-type-printable">Creating Custom Qt Types</a> documents.</p>
<hr />
<h2>Member Function Documentation</h2>
<a name="//apple_ref/cpp/instm/QDebug/QDebug" />
<h3 class="fn"><a name="QDebugx"></a>QDebug::QDebug ( <a href="qiodevice.html">QIODevice</a> * <i>device</i> )</h3>
<p>Constructs a debug stream that writes to the given <i>device</i>.</p>
<h3 class="fn"><a name="QDebug-2"></a>QDebug::QDebug ( <a href="qstring.html">QString</a> * <i>string</i> )</h3>
<p>Constructs a debug stream that writes to the given <i>string</i>.</p>
<h3 class="fn"><a name="QDebug-3"></a>QDebug::QDebug ( <a href="qtglobal.html#QtMsgType-enum">QtMsgType</a> <i>type</i> )</h3>
<p>Constructs a debug stream that writes to the handler for the message type specified by <i>type</i>.</p>
<h3 class="fn"><a name="QDebug-4"></a>QDebug::QDebug ( const QDebug & <i>other</i> )</h3>
<p>Constructs a copy of the <i>other</i> debug stream.</p>
<a name="//apple_ref/cpp/instm/QDebug/~QDebug" />
<h3 class="fn"><a name="dtor.QDebug"></a>QDebug::~QDebug ()</h3>
<p>Flushes any pending data to be written and destroys the debug stream.</p>
<a name="//apple_ref/cpp/instm/QDebug/maybeSpace" />
<h3 class="fn"><a name="maybeSpace"></a>QDebug & QDebug::maybeSpace ()</h3>
<p>Writes a space character to the debug stream, depending on the last character sent to the stream, and returns a reference to the stream.</p>
<p>If the last character was a space character, this function writes a space character to the stream; otherwise, no characters are written to the stream.</p>
<p>See also <a href="qdebug.html#space">space</a>() and <a href="qdebug.html#nospace">nospace</a>().</p>
<a name="//apple_ref/cpp/instm/QDebug/nospace" />
<h3 class="fn"><a name="nospace"></a>QDebug & QDebug::nospace ()</h3>
<p>Clears the stream's internal flag that records whether the last character was a space and returns a reference to the stream.</p>
<p>See also <a href="qdebug.html#space">space</a>() and <a href="qdebug.html#maybeSpace">maybeSpace</a>().</p>
<a name="//apple_ref/cpp/instm/QDebug/space" />
<h3 class="fn"><a name="space"></a>QDebug & QDebug::space ()</h3>
<p>Writes a space character to the debug stream and returns a reference to the stream.</p>
<p>The stream will record that the last character sent to the stream was a space.</p>
<p>See also <a href="qdebug.html#nospace">nospace</a>() and <a href="qdebug.html#maybeSpace">maybeSpace</a>().</p>
<a name="//apple_ref/cpp/instm/QDebug/operator<<" />
<h3 class="fn"><a name="operator-lt-lt"></a>QDebug & QDebug::operator<< ( <a href="qchar.html">QChar</a> <i>t</i> )</h3>
<p>Writes the character, <i>t</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-3"></a>QDebug & QDebug::operator<< ( bool <i>t</i> )</h3>
<p>Writes the boolean value, <i>t</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-4"></a>QDebug & QDebug::operator<< ( char <i>t</i> )</h3>
<p>Writes the character, <i>t</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-5"></a>QDebug & QDebug::operator<< ( signed short <i>i</i> )</h3>
<p>Writes the signed short integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-6"></a>QDebug & QDebug::operator<< ( unsigned short <i>i</i> )</h3>
<p>Writes then unsigned short integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-7"></a>QDebug & QDebug::operator<< ( signed int <i>i</i> )</h3>
<p>Writes the signed integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-8"></a>QDebug & QDebug::operator<< ( unsigned int <i>i</i> )</h3>
<p>Writes then unsigned integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-9"></a>QDebug & QDebug::operator<< ( signed long <i>l</i> )</h3>
<p>Writes the signed long integer, <i>l</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-10"></a>QDebug & QDebug::operator<< ( unsigned long <i>l</i> )</h3>
<p>Writes then unsigned long integer, <i>l</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-11"></a>QDebug & QDebug::operator<< ( <a href="qtglobal.html#qint64-typedef">qint64</a> <i>i</i> )</h3>
<p>Writes the signed 64-bit integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-12"></a>QDebug & QDebug::operator<< ( <a href="qtglobal.html#quint64-typedef">quint64</a> <i>i</i> )</h3>
<p>Writes then unsigned 64-bit integer, <i>i</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-13"></a>QDebug & QDebug::operator<< ( float <i>f</i> )</h3>
<p>Writes the 32-bit floating point number, <i>f</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-14"></a>QDebug & QDebug::operator<< ( double <i>f</i> )</h3>
<p>Writes the 64-bit floating point number, <i>f</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-15"></a>QDebug & QDebug::operator<< ( const char * <i>s</i> )</h3>
<p>Writes the '\0'-terminated string, <i>s</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-16"></a>QDebug & QDebug::operator<< ( const <a href="qstring.html">QString</a> & <i>s</i> )</h3>
<p>Writes the string, <i>s</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-17"></a>QDebug & QDebug::operator<< ( const <a href="qstringref.html">QStringRef</a> & <i>s</i> )</h3>
<p>Writes the string reference, <i>s</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-18"></a>QDebug & QDebug::operator<< ( const <a href="qlatin1string.html">QLatin1String</a> & <i>s</i> )</h3>
<p>Writes the Latin1-encoded string, <i>s</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-19"></a>QDebug & QDebug::operator<< ( const <a href="qbytearray.html">QByteArray</a> & <i>b</i> )</h3>
<p>Writes the byte array, <i>b</i>, to the stream and returns a reference to the stream.</p>
<h3 class="fn"><a name="operator-lt-lt-20"></a>QDebug & QDebug::operator<< ( const void * <i>p</i> )</h3>
<p>Writes a pointer, <i>p</i>, to the stream and returns a reference to the stream.</p>
<a name="//apple_ref/cpp/instm/QDebug/operator=" />
<h3 class="fn"><a name="operator-eq"></a>QDebug & QDebug::operator= ( const QDebug & <i>other</i> )</h3>
<p>Assigns the <i>other</i> debug stream to this stream and returns a reference to this stream.</p>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="40%" align="left">Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies)</td>
<td width="20%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="40%" align="right"><div align="right">Qt 4.6.0</div></td>
<script type="text/javascript" src="http://www.google.com/jsapi"></script><script type="text/javascript">google.load("elements", "1", {packages: "transliteration"});</script><script type="text/javascript" src="http://www.google.com/coop/cse/t13n?form=cse-search-box&t13n_langs=en"></script><script type="text/javascript" src="http://www.google.com/coop/cse/brand?form=cse-search-box&lang=en"></script></tr></table></div></address></body>
</html>
|