mingw/info/stabs/Based-Variables.html

   1 <html lang="en">
   2 <head>
   3 <title>STABS</title>
   4 <meta http-equiv="Content-Type" content="text/html">
   5 <meta name="description" content="STABS">
   6 <meta name="generator" content="makeinfo 4.3">
   7 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home">
   8 </head>
   9 <body>
  10 <div class="node">
  11 <p>
  12 Node:<a name="Based%20Variables">Based Variables</a>,
  13 Next:<a rel="next" accesskey="n" href="Parameters.html#Parameters">Parameters</a>,
  14 Previous:<a rel="previous" accesskey="p" href="Statics.html#Statics">Statics</a>,
  15 Up:<a rel="up" accesskey="u" href="Variables.html#Variables">Variables</a>
  16 <hr><br>
  17 </div>
  18
  19 <h3 class="section">Fortran Based Variables</h3>
  20
  21    <p>Fortran (at least, the Sun and SGI dialects of FORTRAN-77) has a feature
  22 which allows allocating arrays with <code>malloc</code>, but which avoids
  23 blurring the line between arrays and pointers the way that C does.  In
  24 stabs such a variable uses the <code>b</code> symbol descriptor.
  25
  26    <p>For example, the Fortran declarations
  27
  28 <pre class="example">     real foo, foo10(10), foo10_5(10,5)
  29      pointer (foop, foo)
  30      pointer (foo10p, foo10)
  31      pointer (foo105p, foo10_5)
  32      </pre>
  33
  34    <p>produce the stabs
  35
  36 <pre class="example">     foo:b6
  37      foo10:bar3;1;10;6
  38      foo10_5:bar3;1;5;ar3;1;10;6
  39      </pre>
  40
  41    <p>In this example, <code>real</code> is type 6 and type 3 is an integral type
  42 which is the type of the subscripts of the array (probably
  43 <code>integer</code>).
  44
  45    <p>The <code>b</code> symbol descriptor is like <code>V</code> in that it denotes a
  46 statically allocated symbol whose scope is local to a function; see
  47 See <a href="Statics.html#Statics">Statics</a>.  The value of the symbol, instead of being the address
  48 of the variable itself, is the address of a pointer to that variable.
  49 So in the above example, the value of the <code>foo</code> stab is the address
  50 of a pointer to a real, the value of the <code>foo10</code> stab is the
  51 address of a pointer to a 10-element array of reals, and the value of
  52 the <code>foo10_5</code> stab is the address of a pointer to a 5-element array
  53 of 10-element arrays of reals.
  54
  55    </body></html>
  56