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<refentry id="pvsbuffer">
<indexterm id="Indexpvsbuffer"><primary>pvsbuffer</primary></indexterm>
<refentryinfo><title>Spectral Processing:Streaming</title></refentryinfo>
<refmeta>
<refentrytitle>pvsbuffer</refentrytitle>
</refmeta>
<refnamediv>
<refname>pvsbuffer</refname>
<refpurpose>
This opcode creates and writes to a circular buffer for f-signals (streaming PV signals).
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
This opcode sets up and writes to a circular buffer of length ilen (secs),
giving a handle for the buffer and a time pointer, which holds the
current write position (also in seconds). It can be used with one or
more <link linkend="pvsbufread"><citetitle>pvsbufread</citetitle></link> opcodes. Writing is circular, wrapping around at the
end of the buffer.
</para>
</refsect1>
<refsect1>
<title>Syntax</title>
<synopsis>ihandle, ktime <command>pvsbuffer</command> fsig, ilen </synopsis>
</refsect1>
<refsect1>
<title>Initialisation</title>
<para>
<emphasis>ihandle</emphasis> -- handle identifying this particular buffer, which should be passed to a reader opcode.
</para>
<para>
<emphasis>ilen</emphasis> -- buffer length in seconds.
</para>
<title>Performance</title>
<para>
<emphasis>fsig</emphasis> -- an input pv stream
</para>
<para>
<emphasis>ktime</emphasis> -- the current time of writing in the buffer
</para>
<para>
<emphasis>pvsbuffer</emphasis> stores <emphasis>fsig</emphasis> in a buffer which can be read by <link linkend="pvsbufread"><citetitle>pvsbufread</citetitle></link> using the handle <emphasis>ihandle</emphasis>. Different buffers will have different handles so they can be read independently by different <link linkend="pvsbufread"><citetitle>pvsbufread</citetitle></link> opcodes. <emphasis>pvsbuffer</emphasis> gives in its output the current time (<emphasis>ktime</emphasis>) inside the ring buffer which has just been written.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
See <link linkend="pvsbufread"><citetitle>pvsbufread</citetitle></link> for examples of the pvsbuffer opcode.
</para>
</refsect1>
<refsect1>
<title>See also</title>
<para>
<link linkend="pvsbufread"><citetitle>pvsbufread</citetitle></link>
</para>
</refsect1>
<refsect1>
<title>Credits</title>
<para>
<simplelist>
<member>Author: &namevictor;</member>
<member>July 2007</member>
</simplelist>
</para>
</refsect1>
</refentry>
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