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<h2>Foundation</h2>
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<!--Weave of 'Error Messages' generated by 7-->
<ul class="crumbs"><li><a href="../webs.html">Source</a></li><li><a href="index.html">foundation</a></li><li><a href="index.html#3">Chapter 3: The Operating System</a></li><li><b>Error Messages</b></li></ul><p class="purpose">A basic system for command-line tool error messages.</p>
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<ul class="toc"><li><a href="#SP1">&#167;1. Errors handler</a></li><li><a href="#SP2">&#167;2. Error messages</a></li><li><a href="#SP4">&#167;4. Deliberately crashing</a></li><li><a href="#SP5">&#167;5. Survivable errors</a></li></ul><hr class="tocbar">
<p class="inwebparagraph"><a id="SP1"></a><b>&#167;1. Errors handler. </b>The user can provide a routine to deal with error messages before they're
issued. If this returns <code class="display"><span class="extract">FALSE</span></code>, nothing is printed to <code class="display"><span class="extract">stderr</span></code>.
</p>
<pre class="display">
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<span class="reserved">int</span><span class="plain"> (*</span><span class="identifier">errors_handler</span><span class="plain">)(</span><span class="reserved">text_stream</span><span class="plain"> *, </span><span class="reserved">int</span><span class="plain">) = </span><span class="identifier">NULL</span><span class="plain">;</span>
<span class="reserved">void</span><span class="plain"> (*</span><span class="identifier">internal_errors_handler</span><span class="plain">)(</span><span class="reserved">void</span><span class="plain"> *, </span><span class="reserved">char</span><span class="plain"> *, </span><span class="reserved">char</span><span class="plain"> *, </span><span class="reserved">int</span><span class="plain">) = </span><span class="identifier">NULL</span><span class="plain">;</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::set_handler</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> (*</span><span class="identifier">f</span><span class="plain">)(</span><span class="reserved">text_stream</span><span class="plain"> *, </span><span class="reserved">int</span><span class="plain">)) {</span>
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<span class="identifier">errors_handler</span><span class="plain"> = </span><span class="identifier">f</span><span class="plain">;</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::set_internal_handler</span><span class="plain">(</span><span class="reserved">void</span><span class="plain"> (*</span><span class="identifier">f</span><span class="plain">)(</span><span class="reserved">void</span><span class="plain"> *, </span><span class="reserved">char</span><span class="plain"> *, </span><span class="reserved">char</span><span class="plain"> *, </span><span class="reserved">int</span><span class="plain">)) {</span>
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<span class="identifier">internal_errors_handler</span><span class="plain"> = </span><span class="identifier">f</span><span class="plain">;</span>
<span class="plain">}</span>
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<span class="reserved">int</span><span class="plain"> </span><span class="identifier">problem_count</span><span class="plain"> = </span><span class="constant">0</span><span class="plain">;</span>
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Errors::have_occurred</span><span class="plain">(</span><span class="reserved">void</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">problem_count</span><span class="plain"> &gt; </span><span class="constant">0</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="constant">TRUE</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="constant">FALSE</span><span class="plain">;</span>
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<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="reserved">text_stream</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">fatality</span><span class="plain">) {</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">rv</span><span class="plain"> = </span><span class="constant">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">errors_handler</span><span class="plain">) </span><span class="identifier">rv</span><span class="plain"> = (*</span><span class="identifier">errors_handler</span><span class="plain">)(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">fatality</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rv</span><span class="plain">) </span><span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="constant">STDERR</span><span class="plain">, </span><span class="string">"%S"</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">fatality</span><span class="plain">) </span><span class="functiontext">Errors::die</span><span class="plain">(); </span><span class="reserved">else</span><span class="plain"> </span><span class="identifier">problem_count</span><span class="plain">++;</span>
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<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::set_handler appears nowhere else.</p>
<p class="endnote">The function Errors::set_internal_handler appears nowhere else.</p>
<p class="endnote">The function Errors::have_occurred is used in 2/str (<a href="2-str.html#SP37">&#167;37</a>).</p>
<p class="endnote">The function Errors::issue is used in <a href="#SP2">&#167;2</a>, <a href="#SP6">&#167;6</a>, <a href="#SP7">&#167;7</a>.</p>
<p class="inwebparagraph"><a id="SP2"></a><b>&#167;2. Error messages. </b>Ah, they kill you; or they don't. The fatal kind cause an exit code of 2, to
distinguish this from a proper completion in which non-fatal errors occur.
These two routines (alone) can be caused by failures of the memory allocation
or streams systems, and therefore must be written with a little care to use
the temporary stream, not some other string which might need fresh allocation.
</p>
<pre class="display">
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::fatal</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: fatal error: %s\n"</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">TRUE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::fatal_with_C_string</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">parameter</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: fatal error: "</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">);</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">parameter</span><span class="plain">);</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"\n"</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">TRUE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::fatal_with_text</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">text_stream</span><span class="plain"> *</span><span class="identifier">parameter</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: fatal error: "</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">);</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">parameter</span><span class="plain">);</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"\n"</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">TRUE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::fatal_with_file</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">filename</span><span class="plain"> *</span><span class="identifier">F</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: fatal error: %s: %f\n"</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">F</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">TRUE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::fatal_with_path</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">pathname</span><span class="plain"> *</span><span class="identifier">P</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: fatal error: %s: %p\n"</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">P</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">TRUE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::fatal is used in 2/mmr (<a href="2-mmr.html#SP11_1">&#167;11.1</a>, <a href="2-mmr.html#SP15">&#167;15</a>, <a href="2-mmr.html#SP16_1">&#167;16.1</a>), 2/str (<a href="2-str.html#SP34_1">&#167;34.1</a>, <a href="2-str.html#SP35_3">&#167;35.3</a>), 4/cst (<a href="4-cst.html#SP3">&#167;3</a>), 6/bf (<a href="6-bf.html#SP9">&#167;9</a>), 8/bf (<a href="8-bf.html#SP7">&#167;7</a>).</p>
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<p class="endnote">The function Errors::fatal_with_C_string is used in <a href="#SP3">&#167;3</a>, 2/mmr (<a href="2-mmr.html#SP26_1">&#167;26.1</a>).</p>
<p class="endnote">The function Errors::fatal_with_text is used in 3/cla (<a href="3-cla.html#SP8">&#167;8</a>, <a href="3-cla.html#SP11">&#167;11</a>, <a href="3-cla.html#SP13">&#167;13</a>), 8/bdfw (<a href="8-bdfw.html#SP5">&#167;5</a>), 8/bf (<a href="8-bf.html#SP6">&#167;6</a>).</p>
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<p class="endnote">The function Errors::fatal_with_file is used in 4/tf (<a href="4-tf.html#SP5_1">&#167;5.1</a>, <a href="4-tf.html#SP5_2">&#167;5.2</a>, <a href="4-tf.html#SP5_3_2">&#167;5.3.2</a>), 5/ee (<a href="5-ee.html#SP6_1">&#167;6.1</a>, <a href="5-ee.html#SP6_2">&#167;6.2</a>, <a href="5-ee.html#SP6_3">&#167;6.3</a>, <a href="5-ee.html#SP7_2">&#167;7.2</a>, <a href="5-ee.html#SP7_3">&#167;7.3</a>), 6/bf (<a href="6-bf.html#SP7">&#167;7</a>, <a href="6-bf.html#SP8">&#167;8</a>, <a href="6-bf.html#SP9">&#167;9</a>), 8/bf (<a href="8-bf.html#SP4">&#167;4</a>).</p>
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<p class="endnote">The function Errors::fatal_with_path appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP3"></a><b>&#167;3. </b>Assertion failures lead to the following:
</p>
<pre class="definitions">
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<span class="definitionkeyword">define</span> <span class="identifier">internal_error</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">) </span><span class="functiontext">Errors::internal_error_handler</span><span class="plain">(</span><span class="identifier">NULL</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">__FILE__</span><span class="plain">, </span><span class="identifier">__LINE__</span><span class="plain">)</span>
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</pre>
<pre class="display">
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::internal_error_handler</span><span class="plain">(</span><span class="reserved">void</span><span class="plain"> *</span><span class="identifier">p</span><span class="plain">, </span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">f</span><span class="plain">, </span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">lc</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">internal_errors_handler</span><span class="plain">)</span>
<span class="plain">(*</span><span class="identifier">internal_errors_handler</span><span class="plain">)(</span><span class="identifier">p</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">f</span><span class="plain">, </span><span class="identifier">lc</span><span class="plain">);</span>
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<span class="reserved">else</span>
<span class="functiontext">Errors::fatal_with_C_string</span><span class="plain">(</span><span class="string">"internal error (%s)"</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
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<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::internal_error_handler appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP4"></a><b>&#167;4. Deliberately crashing. </b>It's sometimes convenient to get a backtrace from the debugger when an error
occurs unexpectedly, and one way to do that is to force a division by zero.
(This is only enabled by <code class="display"><span class="extract">-crash</span></code> at the command line and is for debugging only.)
</p>
<pre class="display">
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<span class="reserved">int</span><span class="plain"> </span><span class="identifier">debugger_mode</span><span class="plain"> = </span><span class="constant">FALSE</span><span class="plain">;</span>
<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::enter_debugger_mode</span><span class="plain">(</span><span class="reserved">void</span><span class="plain">) {</span>
<span class="identifier">debugger_mode</span><span class="plain"> = </span><span class="constant">TRUE</span><span class="plain">;</span>
<span class="identifier">printf</span><span class="plain">(</span><span class="string">"(Debugger mode enabled: will crash on fatal errors)\n"</span><span class="plain">);</span>
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<span class="plain">}</span>
<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::die</span><span class="plain">(</span><span class="reserved">void</span><span class="plain">) { </span><span class="comment"> as void as it gets</span>
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<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">DL</span><span class="plain">) </span><span class="identifier">STREAM_FLUSH</span><span class="plain">(</span><span class="identifier">DL</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">debugger_mode</span><span class="plain">) {</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="constant">STDERR</span><span class="plain">, </span><span class="string">"(crashing intentionally to allow backtrace)\n"</span><span class="plain">);</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">to_deliberately_crash</span><span class="plain"> = </span><span class="constant">0</span><span class="plain">;</span>
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<span class="identifier">printf</span><span class="plain">(</span><span class="string">"%d"</span><span class="plain">, </span><span class="constant">1</span><span class="plain">/</span><span class="identifier">to_deliberately_crash</span><span class="plain">);</span>
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<span class="plain">}</span>
<span class="comment"> on a fatal exit, memory isn't freed, because that causes threading problems</span>
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<span class="identifier">exit</span><span class="plain">(2);</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::enter_debugger_mode is used in 3/cla (<a href="3-cla.html#SP13_1">&#167;13.1</a>).</p>
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<p class="endnote">The function Errors::die is used in <a href="#SP1">&#167;1</a>.</p>
<p class="inwebparagraph"><a id="SP5"></a><b>&#167;5. Survivable errors. </b>The trick with error messages is to indicate where they occur, and we can
specify this at three levels of abstraction:
</p>
<pre class="display">
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::nowhere</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">) {</span>
<span class="functiontext">Errors::in_text_file</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">NULL</span><span class="plain">);</span>
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<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::in_text_file</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">text_file_position</span><span class="plain"> *</span><span class="identifier">here</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">here</span><span class="plain">)</span>
<span class="functiontext">Errors::at_position</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">here</span><span class="plain">-&gt;</span><span class="element">text_file_filename</span><span class="plain">, </span><span class="identifier">here</span><span class="plain">-&gt;</span><span class="element">line_count</span><span class="plain">);</span>
<span class="reserved">else</span>
<span class="functiontext">Errors::at_position</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">NULL</span><span class="plain">, </span><span class="constant">0</span><span class="plain">);</span>
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<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::in_text_file_S</span><span class="plain">(</span><span class="reserved">text_stream</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">text_file_position</span><span class="plain"> *</span><span class="identifier">here</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">here</span><span class="plain">)</span>
<span class="functiontext">Errors::at_position_S</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">here</span><span class="plain">-&gt;</span><span class="element">text_file_filename</span><span class="plain">, </span><span class="identifier">here</span><span class="plain">-&gt;</span><span class="element">line_count</span><span class="plain">);</span>
<span class="reserved">else</span>
<span class="functiontext">Errors::at_position_S</span><span class="plain">(</span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">NULL</span><span class="plain">, </span><span class="constant">0</span><span class="plain">);</span>
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<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::nowhere is used in 5/ee (<a href="5-ee.html#SP7_2_2_3">&#167;7.2.2.3</a>).</p>
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<p class="endnote">The function Errors::in_text_file is used in 3/cla (<a href="3-cla.html#SP11">&#167;11</a>), 8/bf (<a href="8-bf.html#SP3">&#167;3</a>).</p>
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<p class="endnote">The function Errors::in_text_file_S is used in 8/ws (<a href="8-ws.html#SP7_3_2">&#167;7.3.2</a>, <a href="8-ws.html#SP7_3_2_1">&#167;7.3.2.1</a>, <a href="8-ws.html#SP7_3_3_2">&#167;7.3.3.2</a>).</p>
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<p class="inwebparagraph"><a id="SP6"></a><b>&#167;6. </b>Which funnel through:
</p>
<pre class="display">
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::at_position</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">filename</span><span class="plain"> *</span><span class="identifier">file</span><span class="plain">, </span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">line</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: "</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">);</span>
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<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">file</span><span class="plain">) </span><span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%f, line %d: "</span><span class="plain">, </span><span class="identifier">file</span><span class="plain">, </span><span class="identifier">line</span><span class="plain">);</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s\n"</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">FALSE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::at_position_S</span><span class="plain">(</span><span class="reserved">text_stream</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">filename</span><span class="plain"> *</span><span class="identifier">file</span><span class="plain">, </span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">line</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: "</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">);</span>
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<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">file</span><span class="plain">) </span><span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%f, line %d: "</span><span class="plain">, </span><span class="identifier">file</span><span class="plain">, </span><span class="identifier">line</span><span class="plain">);</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%S\n"</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">FALSE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::at_position is used in <a href="#SP5">&#167;5</a>.</p>
<p class="endnote">The function Errors::at_position_S is used in <a href="#SP5">&#167;5</a>.</p>
<p class="inwebparagraph"><a id="SP7"></a><b>&#167;7. </b>Lastly:
</p>
<pre class="display">
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::with_file</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">filename</span><span class="plain"> *</span><span class="identifier">F</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: %f: %s\n"</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">, </span><span class="identifier">F</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">FALSE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
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<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Errors::with_text</span><span class="plain">(</span><span class="reserved">char</span><span class="plain"> *</span><span class="identifier">message</span><span class="plain">, </span><span class="reserved">text_stream</span><span class="plain"> *</span><span class="identifier">T</span><span class="plain">) {</span>
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<span class="identifier">TEMPORARY_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"%s: "</span><span class="plain">, </span><span class="identifier">INTOOL_NAME</span><span class="plain">);</span>
<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="identifier">message</span><span class="plain">, </span><span class="identifier">T</span><span class="plain">);</span>
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<span class="identifier">WRITE_TO</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="string">"\n"</span><span class="plain">);</span>
<span class="functiontext">Errors::issue</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">, </span><span class="constant">FALSE</span><span class="plain">);</span>
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<span class="identifier">DISCARD_TEXT</span><span class="plain">(</span><span class="identifier">ERM</span><span class="plain">)</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Errors::with_file is used in 4/tf (<a href="4-tf.html#SP5_1">&#167;5.1</a>, <a href="4-tf.html#SP5_2">&#167;5.2</a>, <a href="4-tf.html#SP5_3_2">&#167;5.3.2</a>).</p>
<p class="endnote">The function Errors::with_text is used in 8/bf (<a href="8-bf.html#SP9">&#167;9</a>).</p>
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<hr class="tocbar">
<ul class="toc"><li><i>(This section begins Chapter 3: The Operating System.)</i></li><li><a href="3-cla.html">Continue with 'Command Line Arguments'</a></li></ul><hr class="tocbar">
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