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<h4 class="subsection">3.3.2 Raw Files</h4>

<p>Some low level operations involving lists and data files are provided by
these functions, which are declared in the header file <samp><span class="file">rawio.h</span></samp>.

<div class="defun">
&mdash; Function: list <b>avm_received_list</b> (<var>FILE *object, char *filename</var>)<var><a name="index-avm_005freceived_005flist-547"></a></var><br>
<blockquote><p>This function is a convenient way of transferring data directly from a
raw format file into a list in memory. It might typically be used to
load the virtual code for an application that has been written to a file
by a compiler.

          <dl>
<dt><var>object</var><dd>is the address of a file which should
already be open for reading before this function is called, and will be
read from its current position. 
<br><dt><var>filename</var><dd>should be set by the caller to the address of a null terminated string
containing the name of the file, but is not used unless it needs to be
printed as part of an error message. If it is a null pointer, standard
input is assumed. 
</dl>

        <p>The result returned is a list containing data read from the file.

        <p>The file format is described in <a href="File-Format.html#File-Format">File Format</a>. The preamble section
of the file, if any, is ignored. If the file ends prematurely or
otherwise conflicts with the format, the program is aborted with a
message of
<a name="index-g_t_0040code_007binvalid-raw-file-format_007d-548"></a>
     <pre class="display">          <var>program-name</var><code>: invalid raw file format in </code><var>filename</var>
</pre>
        <p>written to standard error. The program will also be aborted by this
function in the event of a memory overflow.

        <p>The file is left open when this function returns, and could therefore be
used to store other data after the end of the list. The end of a list is
detected automatically by this function, and it reads no further,
leaving the file position on the next character, if any. 
</p></blockquote></div>

<div class="defun">
&mdash; Function: void <b>avm_send_list</b> (<var>FILE *repository, list operand, char *filename</var>)<var><a name="index-avm_005fsend_005flist-549"></a></var><br>
<blockquote><p>This function can be used to transfer data from a list in memory to a
file, essentially by implementing the printing algorithm described in
<a href="Bit-String-Encoding.html#Bit-String-Encoding">Bit String Encoding</a>.

          <dl>
<dt><var>repository</var><dd>is the address of a file already open for writing, to which the data are
written starting from the current position. 
<br><dt><var>operand</var><dd>is the list containing the data to be written
<br><dt><var>filename</var><dd>is the address of a null terminated string containing the name of the
file that will be reported in an error message if necessary. 
</dl>

        <p>No preamble section is written by this function, but one could be
<a name="index-preamble-550"></a>written to the file by the caller prior to calling it.  Error messages
are possible either because of i/o errors or because of insufficient
memory. I/o errors are not fatal and will result only in a warning
message being printed to standard error, but a memory overflow will
cause the process to abort. An i/o error message reported by this
function would be of the form
<a name="index-g_t_0040code_007bcan_0027t-write_007d-551"></a>
     <pre class="display">          <var>program-name</var><code>: can't write to </code><var>filename</var>
</pre>
        <p>followed by the diagnostic obtained from the standard <code>strerror</code>
<a name="index-g_t_0040code_007bstrerror_007d-552"></a>function if it exists on the host platform. The file is left open when
this function returns. 
</p></blockquote></div>

<div class="defun">
&mdash; Function: void <b>avm_initialize_rawio</b> ()<var><a name="index-avm_005finitialize_005frawio-553"></a></var><br>
<blockquote><p>This function initializes some necessary data structures for the
functions in this section, and should be called prior to them at the
beginning of a run. 
</p></blockquote></div>

<div class="defun">
&mdash; Function: void <b>avm_count_rawio</b> ()<var><a name="index-avm_005fcount_005frawio-554"></a></var><br>
<blockquote><p>This function does nothing in the present version of the library, but
should be called after the last call to all of the other functions in
this section in order to maintain compatibility with future versions of
the library. Future versions may decide to use this function to do some
cleaning up of local data structures. 
</p></blockquote></div>

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