mingw/info/gdb/Locations.html

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  12 Node:<a name="Locations">Locations</a>,
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  19 <h5 class="subsubsection">Locations and their accesses</h5>
  20
  21    <p>A location in Chill is an object which can contain values.
  22
  23    <p>A value of a location is generally accessed by the (declared) name of
  24 the location.  The output conforms to the specification of values in
  25 Chill programs.  How values are specified
  26 is the topic of the next section, <a href="Values-and-their-Operations.html#Values%20and%20their%20Operations">Values and their Operations</a>.
  27
  28    <p>The pseudo-location <code>RESULT</code> (or <code>result</code>) can be used to
  29 display or change the result of a currently-active procedure:
  30
  31 <pre class="smallexample">     set result := EXPR
  32      </pre>
  33
  34 <p>This does the same as the Chill action <code>RESULT EXPR</code> (which
  35 is not available in GDB).
  36
  37    <p>Values of reference mode locations are printed by <code>PTR(&lt;hex
  38 value&gt;)</code> in case of a free reference mode, and by <code>(REF &lt;reference
  39 mode&gt;) (&lt;hex-value&gt;)</code> in case of a bound reference.  <code>&lt;hex value&gt;</code>
  40 represents the address where the reference points to.  To access the
  41 value of the location referenced by the pointer, use the dereference
  42 operator <code>-&gt;</code>.
  43
  44    <p>Values of procedure mode locations are displayed by
  45 <pre class="smallexample">     <code>{ PROC
  46      (&lt;argument modes&gt; ) &lt;return mode&gt; } &lt;address&gt; &lt;name of procedure
  47      location&gt;</code>
  48      </pre>
  49    <code>&lt;argument modes&gt;</code> is a list of modes according to the parameter
  50 specification of the procedure and <code>&lt;address&gt;</code> shows the address of
  51 the entry point.
  52
  53    <p>Substructures of string mode-, array mode- or structure mode-values
  54 (e.g. array slices, fields of structure locations) are accessed using
  55 certain operations which are described in the next section, <a href="Values-and-their-Operations.html#Values%20and%20their%20Operations">Values and their Operations</a>.
  56
  57    <p>A location value may be interpreted as having a different mode using the
  58 location conversion.  This mode conversion is written as <code>&lt;mode
  59 name&gt;(&lt;location&gt;)</code>.  The user has to consider that the sizes of the modes
  60 have to be equal otherwise an error occurs.  Furthermore, no range
  61 checking of the location against the destination mode is performed, and
  62 therefore the result can be quite confusing.
  63
  64 <pre class="smallexample">     (gdb) print int (s(3 up 4)) XXX TO be filled in !! XXX
  65      </pre>
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