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<div class="section-level-extent" id="Conditions">
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<p>
Next: <a href="Symbols.html" accesskey="n" rel="next">Symbols</a>, Previous: <a href="Structures.html" accesskey="p" rel="prev">Structures</a>, Up: <a href="Standards.html" accesskey="u" rel="up">Standards</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indexes.html" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Conditions-1">2.7 Conditions</h3>
<ul class="mini-toc">
<li><a href="Conditions.html#C-Reference-7" accesskey="1">C Reference</a></li>
</ul>
<div class="subsection-level-extent" id="C-Reference-7">
<h4 class="subsection">2.7.1 C Reference</h4>
<a class="anchor" id="ECL_005fHANDLER_005fCASE"></a><a class="index-entry-id" id="index-ECL_005fHANDLER_005fCASE"></a>
<dl class="first-deffn">
<dt class="deffn" id="index-ECL_005fHANDLER_005fCASE-1"><span class="category-def">Macro: </span><span><strong class="def-name">ECL_HANDLER_CASE</strong><a class="copiable-link" href='Conditions.html#index-ECL_005fHANDLER_005fCASE-1'> &para;</a></span></dt>
<dd><p>C macro for <a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/m_hand_1.htm">handler-case</a>
</p>
<p><b class="b">Synopsis</b>
</p>
<div class="example">
<pre class="verbatim">ECL_HANDLER_CASE_BEGIN(env,names) {
} ECL_HANDLER_CASE(n,condition) { {
} ECL_HANDLER_CASE_END;
</pre></div>
<p><b class="b">Description</b>
</p>
<p><code class="code">ECL_HANDLER_CASE_BEGIN</code> runs a block of C code with a set of error handlers bound to the names given by the list <var class="var">names</var>. The subsequent <code class="code"><a class="ref" href="Conditions.html#ECL_005fHANDLER_005fCASE">ECL_HANDLER_CASE</a></code> statements specify what to do when the <var class="var">n</var>-th type of conditions is found, where <var class="var">n</var> is an integer denoting the position of the name in the list <var class="var">names</var>.
</p>
<p>When a condition is signaled, ECL scans the list of signal handlers, looking for matches based on <code class="code">typep</code>. If the match with the highest precedence belongs to the list <var class="var">names</var>, ECL will perform a non-local transfer of control to the appropriate <code class="code"><a class="ref" href="Conditions.html#ECL_005fHANDLER_005fCASE">ECL_HANDLER_CASE</a></code>, passing it a <var class="var">condition</var> object as unique argument.
</p>
<p>The following example shows how to establish a handler for <code class="code">error</code> conditions. Note how the first value to <code class="code"><a class="ref" href="Conditions.html#ECL_005fHANDLER_005fCASE">ECL_HANDLER_CASE</a></code> matches the position of the condition name in the list:
</p>
<div class="example">
<pre class="verbatim">cl_object error = ecl_make_symbol(&quot;ERROR&quot;,&quot;CL&quot;);
ECL_HANDLER_CASE_BEGIN(the_env, ecl_list1(error)) {
/* This form is evaluated with bound handlers */
output = cl_eval(1, form);
} ECL_HANDLER_CASE(1, condition) {
/* This code is executed when an error happens */
/* We just return the error that took place */
output = condition;
} ECL_HANDLER_CASE_END;
</pre></div>
</dd></dl>
<a class="anchor" id="ECL_005fRESTART_005fCASE"></a><a class="index-entry-id" id="index-ECL_005fRESTART_005fCASE"></a>
<dl class="first-deffn">
<dt class="deffn" id="index-ECL_005fRESTART_005fCASE-1"><span class="category-def">Macro: </span><span><strong class="def-name">ECL_RESTART_CASE</strong><a class="copiable-link" href='Conditions.html#index-ECL_005fRESTART_005fCASE-1'> &para;</a></span></dt>
<dd><p>C macro for <a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/m_rst_ca.htm">restart-case</a>
</p>
<p><b class="b">Synopsis</b>
</p>
<div class="example">
<pre class="verbatim">ECL_RESTART_CASE_BEGIN(env,names) {
} ECL_RESTART_CASE(n,args) { {
} ECL_RESTART_CASE_END;
</pre></div>
<p><b class="b">Description</b>
</p>
<p><code class="code">ECL_RESTART_CASE_BEGIN</code> runs a block of C code with a set of restarts bound to the names given by the list <var class="var">names</var>. The subsequent <code class="code"><a class="ref" href="Conditions.html#ECL_005fRESTART_005fCASE">ECL_RESTART_CASE</a></code> statements specify what to do when the <var class="var">n</var>-th restart is invoked, where <var class="var">n</var> is an integer denoting the position of the name in the list <var class="var">names</var>.
</p>
<p>When the restart is invoked, it can receive any number of arguments, which are grouped in a list and stored in a new variable created with the name <var class="var">args</var>.
</p>
<p>The following example shows how to establish an <var class="var">abort</var> and a <var class="var">use-value</var> restart. Note how the first value to <code class="code"><a class="ref" href="Conditions.html#ECL_005fRESTART_005fCASE">ECL_RESTART_CASE</a></code> matches the position of the restart name in the list:
</p>
<div class="example">
<pre class="verbatim">cl_object abort = ecl_make_symbol(&quot;ABORT&quot;,&quot;CL&quot;);
cl_object use_value = ecl_make_symbol(&quot;USE-VALUE&quot;,&quot;CL&quot;);
ECL_RESTART_CASE_BEGIN(the_env, cl_list(2, abort, use_value)) {
/* This form is evaluated with bound restarts */
output = cl_eval(1, form);
} ECL_RESTART_CASE(1, args) {
/* This code is executed when the 1st restart (ABORT) is invoked */
output = ECL_NIL;
} ECL_RESTART_CASE(2, args) {
/* This code is executed when the 2nd restart (USE-VALUE) is invoked */
output = ECL_CAR(args);
} ECL_RESTART_CASE_END;
</pre></div>
</dd></dl>
<ul class="mini-toc">
<li><a href="Conditions.html#ANSI-dictionary" accesskey="1">ANSI dictionary</a></li>
</ul>
<div class="subsubsection-level-extent" id="ANSI-dictionary">
<h4 class="subsubsection">2.7.1.1 ANSI dictionary</h4>
<p>Common Lisp and C equivalence
</p>
<table class="multitable">
<thead><tr><th width="30%">Lisp symbol</th><th width="70%">C function</th></tr></thead>
<tbody><tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_abortc.htm">abort</a></td><td width="70%">cl_object cl_abort(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_break.htm">break</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_cell_e.htm">cell-error-name</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_cerror.htm">cerror</a></td><td width="70%">cl_object cl_cerror(cl_narg narg, cl_object continue_format_control, cl_object datum, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_comp_1.htm">compute-restarts</a></td><td width="70%">cl_object cl_compute_restarts(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_abortc.htm">continue</a></td><td width="70%">cl_object cl_continue(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_error.htm">error</a></td><td width="70%">cl_object cl_error(cl_narg narg, cl_object datum, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_find_r.htm">find-restart</a></td><td width="70%">cl_object cl_find_restart(cl_narg narg, cl_object identifier, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/m_hand_1.htm">handler-case</a></td><td width="70%">ECL_HANDLER_CASE macro</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_invali.htm">invalid-method-error</a></td><td width="70%">cl_object cl_invalid_method_error (cl_narg narg, cl_object method, cl_object format, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_invoke.htm">invoke-debugger</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_invo_1.htm">invoke-restart</a></td><td width="70%">cl_object cl_invoke_restart(cl_narg narg, cl_object restart, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_invo_2.htm">invoke-restart-interactively</a></td><td width="70%">cl_object cl_invoke_restart_interactively(cl_object restart)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_mk_cnd.htm">make-condition</a></td><td width="70%">cl_make_condition(cl_narg narg, cl_object type, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_meth_1.htm">method-combination-error</a></td><td width="70%">cl_object cl_method_combination_error(cl_narg narg, cl_object format, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_abortc.htm">muffle-warning</a></td><td width="70%">cl_object cl_muffle_warning(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_rst_na.htm">restart-name</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_rst_ca.htm">restart-case</a></td><td width="70%">ECL_RESTART_CASE macro</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_signal.htm">signal</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_smp_cn.htm">simple-condition-format-control</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_smp_cn.htm">simple-condition-format-arguments</a></td><td width="70%">[Only in Common Lisp]</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_abortc.htm">store-value</a></td><td width="70%">cl_object cl_store_value(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_abortc.htm">use-value</a></td><td width="70%">cl_object cl_use_value(cl_narg narg, ...)</td></tr>
<tr><td width="30%"><a class="url" href="http://www.lispworks.com/documentation/HyperSpec/Body/f_warn.htm">warn</a></td><td width="70%">[Only in Common Lisp]</td></tr>
</tbody>
</table>
</div>
</div>
</div>
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