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1 <HTML
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2 ><HEAD
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3 ><TITLE
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4 >SDL_SetEventFilter</TITLE
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5 ><META
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6 NAME="GENERATOR"
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.61
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8 "><LINK
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9 REL="HOME"
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10 TITLE="SDL Library Documentation"
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11 HREF="index.html"><LINK
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12 REL="UP"
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13 TITLE="Event Functions."
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14 HREF="eventfunctions.html"><LINK
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15 REL="PREVIOUS"
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16 TITLE="SDL_PushEvent"
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17 HREF="sdlpushevent.html"><LINK
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18 REL="NEXT"
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19 TITLE="SDL_GetEventFilter"
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20 HREF="sdlgeteventfilter.html"></HEAD
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21 ><BODY
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22 CLASS="REFENTRY"
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23 BGCOLOR="#FFF8DC"
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24 TEXT="#000000"
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25 LINK="#0000ee"
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26 VLINK="#551a8b"
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27 ALINK="#ff0000"
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28 ><DIV
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29 CLASS="NAVHEADER"
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30 ><TABLE
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31 WIDTH="100%"
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32 BORDER="0"
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33 CELLPADDING="0"
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34 CELLSPACING="0"
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35 ><TR
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36 ><TH
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37 COLSPAN="3"
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38 ALIGN="center"
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39 >SDL Library Documentation</TH
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40 ></TR
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41 ><TR
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42 ><TD
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43 WIDTH="10%"
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44 ALIGN="left"
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45 VALIGN="bottom"
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46 ><A
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47 HREF="sdlpushevent.html"
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48 >Prev</A
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49 ></TD
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50 ><TD
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51 WIDTH="80%"
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52 ALIGN="center"
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53 VALIGN="bottom"
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54 ></TD
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55 ><TD
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56 WIDTH="10%"
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57 ALIGN="right"
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58 VALIGN="bottom"
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59 ><A
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60 HREF="sdlgeteventfilter.html"
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61 >Next</A
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62 ></TD
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63 ></TR
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64 ></TABLE
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65 ><HR
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66 ALIGN="LEFT"
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67 WIDTH="100%"></DIV
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68 ><H1
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69 ><A
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70 NAME="SDLSETEVENTFILTER"
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71 >SDL_SetEventFilter</A
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72 ></H1
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73 ><DIV
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74 CLASS="REFNAMEDIV"
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75 ><A
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76 NAME="AEN4957"
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77 ></A
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78 ><H2
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79 >Name</H2
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80 >SDL_SetEventFilter -- Sets up a filter to process all events before they are posted
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81 to the event queue.</DIV
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82 ><DIV
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83 CLASS="REFSYNOPSISDIV"
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84 ><A
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85 NAME="AEN4960"
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86 ></A
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87 ><H2
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88 >Synopsis</H2
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89 ><DIV
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90 CLASS="FUNCSYNOPSIS"
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91 ><A
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92 NAME="AEN4961"
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93 ></A
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94 ><P
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95 ></P
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96 ><PRE
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97 CLASS="FUNCSYNOPSISINFO"
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98 >#include "SDL.h"</PRE
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99 ><P
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100 ><CODE
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101 ><CODE
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102 CLASS="FUNCDEF"
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103 >void <B
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104 CLASS="FSFUNC"
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105 >SDL_SetEventFilter</B
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106 ></CODE
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107 >(SDL_EventFilter filter);</CODE
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108 ></P
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109 ><P
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110 ></P
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111 ></DIV
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112 ></DIV
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113 ><DIV
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114 CLASS="REFSECT1"
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115 ><A
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116 NAME="AEN4967"
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117 ></A
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118 ><H2
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119 >Description</H2
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120 ><P
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121 >This function sets up a filter to process all events before they are posted
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122 to the event queue. This is a very powerful and flexible feature. The filter
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123 is prototyped as:
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124 <PRE
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125 CLASS="PROGRAMLISTING"
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126 >typedef int (*SDL_EventFilter)(const SDL_Event *event);</PRE
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127 >
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128 If the filter returns <SPAN
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129 CLASS="RETURNVALUE"
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130 >1</SPAN
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131 >, then the event will be
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132 added to the internal queue. If it returns <SPAN
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133 CLASS="RETURNVALUE"
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134 >0</SPAN
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135 >,
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136 then the event will be dropped from the queue. This allows selective
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137 filtering of dynamically.</P
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138 ><P
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139 >There is one caveat when dealing with the <TT
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140 CLASS="LITERAL"
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141 >SDL_QUITEVENT</TT
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142 > event type. The
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143 event filter is only called when the window manager desires to close the
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144 application window. If the event filter returns 1, then the window will
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145 be closed, otherwise the window will remain open if possible.
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146 If the quit event is generated by an interrupt signal, it will bypass the
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147 internal queue and be delivered to the application at the next event poll.</P
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148 ><DIV
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149 CLASS="NOTE"
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150 ><BLOCKQUOTE
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151 CLASS="NOTE"
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152 ><P
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153 ><B
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154 >Note: </B
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155 >Events pushed onto the queue with <A
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156 HREF="sdlpushevent.html"
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157 ><TT
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158 CLASS="FUNCTION"
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159 >SDL_PushEvent</TT
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160 ></A
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161 > or <A
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162 HREF="sdlpeepevents.html"
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163 ><TT
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164 CLASS="FUNCTION"
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165 >SDL_PeepEvents</TT
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166 ></A
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167 > do not get passed through the event filter.</P
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168 ></BLOCKQUOTE
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169 ></DIV
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170 ><DIV
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171 CLASS="NOTE"
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172 ><BLOCKQUOTE
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173 CLASS="NOTE"
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174 ><P
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175 ><B
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176 >Note: </B
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177 ><I
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178 CLASS="EMPHASIS"
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179 >Be Careful!</I
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180 > The event filter function may run in a different thread so be careful what you do within it.</P
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181 ></BLOCKQUOTE
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182 ></DIV
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183 ></DIV
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184 ><DIV
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185 CLASS="REFSECT1"
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186 ><A
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187 NAME="AEN4984"
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188 ></A
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189 ><H2
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190 >See Also</H2
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191 ><P
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192 ><A
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193 HREF="sdlevent.html"
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194 ><SPAN
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195 CLASS="STRUCTNAME"
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196 >SDL_Event</SPAN
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197 ></A
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198 >,
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199 <A
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200 HREF="sdlgeteventfilter.html"
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201 ><TT
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202 CLASS="FUNCTION"
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203 >SDL_GetEventFilter</TT
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204 ></A
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205 >,
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206 <A
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207 HREF="sdlpushevent.html"
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208 ><TT
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209 CLASS="FUNCTION"
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210 >SDL_PushEvent</TT
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211 ></A
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212 ></P
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213 ></DIV
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214 ><DIV
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215 CLASS="NAVFOOTER"
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216 ><HR
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217 ALIGN="LEFT"
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218 WIDTH="100%"><TABLE
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219 WIDTH="100%"
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220 BORDER="0"
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221 CELLPADDING="0"
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222 CELLSPACING="0"
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223 ><TR
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224 ><TD
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225 WIDTH="33%"
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226 ALIGN="left"
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227 VALIGN="top"
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228 ><A
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229 HREF="sdlpushevent.html"
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230 >Prev</A
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231 ></TD
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232 ><TD
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233 WIDTH="34%"
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234 ALIGN="center"
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235 VALIGN="top"
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236 ><A
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237 HREF="index.html"
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238 >Home</A
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239 ></TD
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240 ><TD
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241 WIDTH="33%"
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242 ALIGN="right"
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243 VALIGN="top"
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244 ><A
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245 HREF="sdlgeteventfilter.html"
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246 >Next</A
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247 ></TD
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248 ></TR
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249 ><TR
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250 ><TD
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251 WIDTH="33%"
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252 ALIGN="left"
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253 VALIGN="top"
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254 >SDL_PushEvent</TD
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255 ><TD
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256 WIDTH="34%"
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257 ALIGN="center"
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258 VALIGN="top"
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259 ><A
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260 HREF="eventfunctions.html"
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261 >Up</A
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262 ></TD
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263 ><TD
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264 WIDTH="33%"
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265 ALIGN="right"
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266 VALIGN="top"
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267 >SDL_GetEventFilter</TD
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268 ></TR
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269 ></TABLE
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270 ></DIV
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271 ></BODY
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272 ></HTML
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273 > |
