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<a name="ATo"></a>
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Next: <a href="ATq.html#ATq" accesskey="n" rel="next">ATq</a>, Previous: <a href="ATO_005f.html#ATO_005f" accesskey="p" rel="prev">ATO_</a>, Up: <a href="AT-commands.html#AT-commands" accesskey="u" rel="up">AT commands</a> &nbsp; [<a href="Parameter-index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-index.html#Concept-index" title="Index" rel="index">Index</a>]</p>
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<a name="g_t_0040o_003a-Open-output-file-_0028local-scope_0029"></a>
<h4 class="subsection">5.5.21 &lsquo;<samp>@o</samp>&rsquo;:  Open output file (local scope)</h4>

<a name="index-_0040o"></a>
<a name="index-File_002c-opening-output-1"></a>
<p>This behaves like &lsquo;<samp>@O</samp>&rsquo;, except that the new file name is in effect only
for the current section.  A subsequent &lsquo;<samp>@o</samp>&rsquo; issued in a different
section but for the same file name accretes material to the file.  
</p>
<p>An annoying problem arises in C programming when &lsquo;<samp>@o</samp>&rsquo;s are used to create
multiple source files that are subsequently compiled under the control
of a <code>Makefile</code>.  Remember that by default line-number information
is written into the C files.  This means that a change in the <code>web</code>
file code for one source file can affect all of the others, because the
line numbering in the <code>web</code> file changes.  Therefore, a trivial change to
the code for just one source file can cause all of the others to be
recompiled.
</p>
<p>As long as one desires debugging information relative to the original
<code>web</code> file, there is really no solution to this problem; one needs
the proper line information in each file in order to work with the
debugger, so if line numbers change the sources must be recompiled.  One
can, of course, turn off the line numbering with the command-line option
&lsquo;<samp>-#</samp>&rsquo; (see <a href="_002d_0023.html#g_t_002d_0023">-#</a>), but then debugger statements will refer to the
tangled C code, which is undesirable.  A better partial solution is to
use &lsquo;<samp>@q</samp>&rsquo; (see <a href="ATq.html#ATq">ATq</a>) to turn off the line numbering for output
code that is currently stable.  In the following example, the code for
each file is put into a module, then the modules are output in the
unnamed section; it is assumed that the programmer is currently
making changes to the code for <samp>file2.c</samp>:
</p>
<div class="example">
<pre class="example">@
@a
@q0
@o file1.c
        @&lt;File 1@&gt;@;
@q1
@o file2.c
        @&lt;File 2@&gt;@;
@q0
@o file3.c
        @&lt;File 3@&gt;@;
</pre></div>

<p>For very large projects, another solution is to maintain multiple
<code>web</code> source files.  To avoid losing the substantial benefits of
the automatic index, refer to the discussion in <a href="Merging-indexes.html#Merging-indexes">Merging indexes</a> to
learn how to create a master index that contains information about
several <code>web</code> files. 
</p>

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fweb-doc 1.62-13 / usr / share / doc / fweb / html-info / ATo.html
