<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>5.3. Memory limits</title><link rel="stylesheet" href="ecl.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"><link rel="home" href="index.html" title="The ECL manual"><link rel="up" href="ch20.html" title="Chapter 5. Memory Management"><link rel="prev" href="ch20s02.html" title="5.2. Boehm-Weiser garbage collector"><link rel="next" href="ch20s04.html" title="5.4. Memory Conditions"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">5.3. Memory limits</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch20s02.html">Prev</a> </td><th width="60%" align="center">Chapter 5. Memory Management</th><td width="20%" align="right"> <a accesskey="n" href="ch20s04.html">Next</a></td></tr></table><hr></div><div class="section" title="5.3. Memory limits"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="ext.memory.limits"></a>5.3. Memory limits</h2></div></div></div><p>Beginning with version 9.2.1, <span class="application">ECL</span> operates a tighter control of the
resources it uses. In particular, it features explicit limits in the four
stacks and in the amount of live data. These limits are optional, can be
changed at run time, but they allow users to better control the
evolution of a program, handling memory and stack overflow gracefully via
the Common Lisp condition system.</p><p>The customizable limits are listed in <a class="xref" href="re34.html#table.memory.limits" title="Table 5.1. Customizable memory limits">Table 5.1</a>, but they need a careful description.</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p><code class="varname">ext:heap-size</code> limits the total amount of
memory which is available for lisp objects. This is the memory used when
you create conses, arrays, structures, etc.</p></li><li class="listitem"><p><code class="varname">ext:c-stack</code> controls the size of the
stack for compiled code, including <span class="application">ECL</span>'s library itself. This limit is
less stringent than the others. For instance, when code is compiled with
low safety settings, checks for this stack limit are usually omitted, for
performance reasons.</p></li><li class="listitem"><p><code class="varname">ext:binding-stack</code> controls the number of
nested bindings for special variables. The current value is usually safe
enough, unless you have deep recursive functions that bind special
variables, which is not really a good idea.</p></li><li class="listitem"><p><code class="varname">ext:frame-stack</code> controls the number of
nested blocks, tagbody and other control structures. It affects both
interpreted and compiled code, but quite often compiled code optimizes away
these stack frames, saving memory and not being affected by this
limit.</p></li><li class="listitem"><p><code class="varname">ext:lisp-stack</code> controls the size of the
interpreter stack. It only affects interpreted code.</p></li></ul></div><p>If you look at <a class="xref" href="re34.html#table.memory.limits" title="Table 5.1. Customizable memory limits">Table 5.1</a>, some of these
limits may seem very stringent, but they exist to allow detecting and
correcting both stack and memory overflow conditions. Larger values can be
set systematically either in the <code class="filename">~/.eclrc</code>
initialization file, or using the command line options from the table.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch20s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch20.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch20s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">5.2. Boehm-Weiser garbage collector </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 5.4. Memory Conditions</td></tr></table></div></body></html>
