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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the documentation of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 /*! |
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43 \class Q3PtrQueue |
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44 \brief The Q3PtrQueue class is a template class that provides a queue. |
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45 \compat |
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46 |
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47 Q3ValueVector can be used as an STL-compatible alternative to this |
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48 class. |
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49 |
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50 A template instance Q3PtrQueue\<X\> is a queue that operates on |
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51 pointers to X (X*). |
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52 |
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53 A queue is a first in, first out structure. Items are added to the |
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54 tail of the queue with enqueue() and retrieved from the head with |
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55 dequeue(). You can peek at the head item without dequeing it using |
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56 head(). |
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57 |
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58 You can control the queue's deletion policy with setAutoDelete(). |
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59 |
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60 For compatibility with the Q3PtrCollection classes, current() and |
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61 remove() are provided; both operate on the head(). |
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62 |
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63 \sa Q3PtrList Q3PtrStack |
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64 */ |
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65 |
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66 /*! |
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67 \fn Q3PtrQueue::Q3PtrQueue () |
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68 |
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69 Creates an empty queue with autoDelete() set to FALSE. |
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70 */ |
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71 |
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72 /*! |
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73 \fn Q3PtrQueue::Q3PtrQueue( const Q3PtrQueue<type>& queue ) |
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74 |
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75 Creates a queue from \a queue. |
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76 |
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77 Only the pointers are copied; the items are not. The autoDelete() |
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78 flag is set to FALSE. |
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79 */ |
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80 |
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81 /*! |
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82 \fn Q3PtrQueue::~Q3PtrQueue() |
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83 |
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84 Destroys the queue. Items in the queue are deleted if autoDelete() |
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85 is TRUE. |
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86 */ |
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87 |
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88 /*! |
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89 \fn Q3PtrQueue<type>& Q3PtrQueue::operator= (const Q3PtrQueue<type>& queue) |
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90 |
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91 Assigns \a queue to this queue and returns a reference to this |
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92 queue. |
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93 |
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94 This queue is first cleared and then each item in \a queue is |
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95 enqueued to this queue. Only the pointers are copied. |
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96 |
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97 \warning The autoDelete() flag is not modified. If it is TRUE for |
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98 both \a queue and this queue, deleting the two lists will cause \e |
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99 double-deletion of the items. |
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100 */ |
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101 |
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102 /*! |
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103 \fn bool Q3PtrQueue::isEmpty() const |
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104 |
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105 Returns TRUE if the queue is empty; otherwise returns FALSE. |
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106 |
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107 \sa count() dequeue() head() |
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108 */ |
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109 |
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110 /*! |
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111 \fn void Q3PtrQueue::enqueue (const type* d) |
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112 |
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113 Adds item \a d to the tail of the queue. |
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114 |
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115 \sa count() dequeue() |
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116 */ |
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117 |
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118 /*! |
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119 \fn type* Q3PtrQueue::dequeue () |
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120 |
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121 Takes the head item from the queue and returns a pointer to it. |
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122 Returns 0 if the queue is empty. |
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123 |
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124 \sa enqueue() count() |
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125 */ |
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126 |
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127 /*! |
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128 \fn bool Q3PtrQueue::remove() |
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129 |
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130 Removes the head item from the queue, and returns TRUE if there |
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131 was an item, i.e. the queue wasn't empty; otherwise returns FALSE. |
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132 |
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133 The item is deleted if autoDelete() is TRUE. |
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134 |
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135 \sa head() isEmpty() dequeue() |
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136 */ |
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137 |
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138 /*! |
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139 \fn void Q3PtrQueue::clear() |
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140 |
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141 Removes all items from the queue, and deletes them if autoDelete() |
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142 is TRUE. |
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143 |
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144 \sa remove() |
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145 */ |
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146 |
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147 /*! |
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148 \fn uint Q3PtrQueue::count() const |
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149 |
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150 Returns the number of items in the queue. |
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151 |
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152 \sa isEmpty() |
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153 */ |
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154 |
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155 /*! |
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156 \fn type* Q3PtrQueue::head() const |
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157 |
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158 Returns a pointer to the head item in the queue. The queue is not |
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159 changed. Returns 0 if the queue is empty. |
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160 |
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161 \sa dequeue() isEmpty() |
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162 */ |
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163 |
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164 /*! |
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165 \fn Q3PtrQueue::operator type*() const |
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166 |
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167 Returns a pointer to the head item in the queue. The queue is not |
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168 changed. Returns 0 if the queue is empty. |
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169 |
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170 \sa dequeue() isEmpty() |
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171 */ |
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172 |
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173 /*! |
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174 \fn type* Q3PtrQueue::current() const |
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175 |
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176 Returns a pointer to the head item in the queue. The queue is not |
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177 changed. Returns 0 if the queue is empty. |
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178 |
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179 \sa dequeue() isEmpty() |
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180 */ |
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181 |
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182 /*! |
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183 \fn bool Q3PtrQueue::autoDelete() const |
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184 |
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185 Returns the setting of the auto-delete option. The default is |
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186 FALSE. |
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187 |
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188 \sa setAutoDelete() |
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189 */ |
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190 |
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191 /*! |
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192 \fn void Q3PtrQueue::setAutoDelete( bool enable ) |
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193 |
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194 Sets the queue to auto-delete its contents if \a enable is TRUE |
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195 and not to delete them if \a enable is FALSE. |
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196 |
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197 If auto-deleting is turned on, all the items in a queue are |
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198 deleted when the queue itself is deleted. This can be quite |
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199 convenient if the queue has the only pointer to the items. |
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200 |
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201 The default setting is FALSE, for safety. If you turn it on, be |
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202 careful about copying the queue: you might find yourself with two |
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203 queues deleting the same items. |
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204 |
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205 \sa autoDelete() |
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206 */ |
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207 |
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208 /*! |
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209 \fn QDataStream& Q3PtrQueue::read( QDataStream& s, |
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210 Q3PtrCollection::Item& item ) |
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211 |
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212 Reads a queue item, \a item, from the stream \a s and returns a |
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213 reference to the stream. |
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214 |
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215 The default implementation sets \a item to 0. |
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216 |
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217 \sa write() |
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218 */ |
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219 |
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220 /*! |
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221 \fn QDataStream& Q3PtrQueue::write( QDataStream& s, |
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222 Q3PtrCollection::Item item ) const |
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223 |
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224 Writes a queue item, \a item, to the stream \a s and returns a |
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225 reference to the stream. |
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226 |
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227 The default implementation does nothing. |
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228 |
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229 \sa read() |
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230 */ |