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<H1>pamvalidate</H1>
Updated: 22 March 2014
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<A HREF="#index">Table Of Contents</A>
<H2>NAME</H2>
pamvalidate - validate Netpbm image format
<H2 id="synopsis">SYNOPSIS</H2>
<B>pamvalidate</B>
<H2 id="description">DESCRIPTION</H2>
<p>This program is part of <a href="index.html">Netpbm</a>.
<p><b>pamvalidate</b> copies a Netpbm image from Standard Input to Standard
Output, except that if there are certain violations of the image format in the
input, <b>pamvalidate</b> fails <em>without producing any output</em>.
<p>This is most useful in a pipeline, before a stage you don't want to start
working on Netpbm input until it knows it can get all the way through it. For
example, assume you are converting PPM images to PNG and you don't want to
produce a partial PNG file under any circumstance. If you just
use <b>pnmtopng</b>, and the PPM input is truncated halfway through the
raster, <b>pnmtopng</b> fails, but also produces about half of a PNG file.
To prevent that, pass your PPM input through <b>pamvalidate</b> on its way
to <b>pnmtopng</b>. Then, <b>pamvalidate</b> will fail, and consequently
the pipeline will fail, before <b>pnmtopng</b> has seen any input and
therefore before <b>pnmtopng</b> has produced any output.
<p>These are the kinds of format violations <b>pamvalidate</b> detects:
<ul>
<li>A purported sample value exceeds the declared maxval.
<li>The stream ends prematurely.
</ul>
<p>This program works on multi-image streams, producing a corresponding output
stream.
<p>See <b>pamfix</b> for a way to salvage an invalid Netpbm image stream.
<H2 id="options">OPTIONS</H2>
<p>None.
<H2 id="seealso">SEE ALSO</H2>
<B><A HREF="pam.html">pam</A></B>
<B><A HREF="pnm.html">pnm</A></B>
<B><A HREF="pamfix.html">pamfix</A></B>
<h2 id="history">HISTORY</h2>
<p><b>pamvalidate</b> was new in Netpbm 10.66 (March 2014).
<HR>
<H2 id="index">Table Of Contents</H2>
<UL>
<LI><A HREF="#synopsis">SYNOPSIS</A>
<LI><A HREF="#description">DESCRIPTION</A>
<LI><A HREF="#options">OPTIONS</A>
<LI><A HREF="#seealso">SEE ALSO</A>
<LI><A HREF="#history">HISTORY</A>
</UL>
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