lttv/doc/developer/developer_guide/html/x81.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
   2 <HTML
   3 ><HEAD
   4 ><TITLE
   5 >How to request background computation</TITLE
   6 ><META
   7 NAME="GENERATOR"
   8 CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
   9 REL="HOME"
  10 TITLE="Linux Trace Toolkit Viewer Developer Guide"
  11 HREF="index.html"><LINK
  12 REL="UP"
  13 TITLE="Linux Trace Toolkit Viewer Graphical Module Tutorial"
  14 HREF="c67.html"><LINK
  15 REL="PREVIOUS"
  16 TITLE="The dynamic part of a module : the viewer"
  17 HREF="x77.html"><LINK
  18 REL="NEXT"
  19 TITLE="How to handle events and use the graphical trace reading service"
  20 HREF="x84.html"></HEAD
  21 ><BODY
  22 CLASS="sect1"
  23 BGCOLOR="#FFFFFF"
  24 TEXT="#000000"
  25 LINK="#0000FF"
  26 VLINK="#840084"
  27 ALINK="#0000FF"
  28 ><DIV
  29 CLASS="NAVHEADER"
  30 ><TABLE
  31 SUMMARY="Header navigation table"
  32 WIDTH="100%"
  33 BORDER="0"
  34 CELLPADDING="0"
  35 CELLSPACING="0"
  36 ><TR
  37 ><TH
  38 COLSPAN="3"
  39 ALIGN="center"
  40 >Linux Trace Toolkit Viewer Developer Guide</TH
  41 ></TR
  42 ><TR
  43 ><TD
  44 WIDTH="10%"
  45 ALIGN="left"
  46 VALIGN="bottom"
  47 ><A
  48 HREF="x77.html"
  49 ACCESSKEY="P"
  50 >Prev</A
  51 ></TD
  52 ><TD
  53 WIDTH="80%"
  54 ALIGN="center"
  55 VALIGN="bottom"
  56 >Chapter 3. Linux Trace Toolkit Viewer Graphical Module Tutorial</TD
  57 ><TD
  58 WIDTH="10%"
  59 ALIGN="right"
  60 VALIGN="bottom"
  61 ><A
  62 HREF="x84.html"
  63 ACCESSKEY="N"
  64 >Next</A
  65 ></TD
  66 ></TR
  67 ></TABLE
  68 ><HR
  69 ALIGN="LEFT"
  70 WIDTH="100%"></DIV
  71 ><DIV
  72 CLASS="sect1"
  73 ><H1
  74 CLASS="sect1"
  75 ><A
  76 NAME="AEN81"
  77 >3.4. How to request background computation</A
  78 ></H1
  79 ><P
  80 >&#13;You will also notice the presence of a request_background_data() called in the
  81 constructor. This function, in eventhooks.c, does verify for the presence of the
  82 state information that could be precomputed by the main window background
  83 computation. If it has not been precomputed, we ask for a computation and show
  84 partial data. We also register a hook that will be called (notified) by the main
  85 window when the requested data will become ready, so the viewer can update
  86 itself with the new data. If no partial information would have made sense in a
  87 particular viewer, one could choose to shown a "waiting for computation" message
  88 while waiting for the notification. See lttvwindow/lttvwindowtraces.h for the API
  89 of the background requests.
  90 </P
  91 ></DIV
  92 ><DIV
  93 CLASS="NAVFOOTER"
  94 ><HR
  95 ALIGN="LEFT"
  96 WIDTH="100%"><TABLE
  97 SUMMARY="Footer navigation table"
  98 WIDTH="100%"
  99 BORDER="0"
 100 CELLPADDING="0"
 101 CELLSPACING="0"
 102 ><TR
 103 ><TD
 104 WIDTH="33%"
 105 ALIGN="left"
 106 VALIGN="top"
 107 ><A
 108 HREF="x77.html"
 109 ACCESSKEY="P"
 110 >Prev</A
 111 ></TD
 112 ><TD
 113 WIDTH="34%"
 114 ALIGN="center"
 115 VALIGN="top"
 116 ><A
 117 HREF="index.html"
 118 ACCESSKEY="H"
 119 >Home</A
 120 ></TD
 121 ><TD
 122 WIDTH="33%"
 123 ALIGN="right"
 124 VALIGN="top"
 125 ><A
 126 HREF="x84.html"
 127 ACCESSKEY="N"
 128 >Next</A
 129 ></TD
 130 ></TR
 131 ><TR
 132 ><TD
 133 WIDTH="33%"
 134 ALIGN="left"
 135 VALIGN="top"
 136 >The dynamic part of a module : the viewer</TD
 137 ><TD
 138 WIDTH="34%"
 139 ALIGN="center"
 140 VALIGN="top"
 141 ><A
 142 HREF="c67.html"
 143 ACCESSKEY="U"
 144 >Up</A
 145 ></TD
 146 ><TD
 147 WIDTH="33%"
 148 ALIGN="right"
 149 VALIGN="top"
 150 >How to handle events and use the graphical trace reading service</TD
 151 ></TR
 152 ></TABLE
 153 ></DIV
 154 ></BODY
 155 ></HTML
 156 >