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<h3 class="section">16.4 Raw Output Internals</h3>
<a name="index-Raw-output-internals"></a>
<p><code>mpz_out_raw</code> uses the following format.
</p>
<div class="example">
<pre class="example">+------+------------------------+
| size | data bytes |
+------+------------------------+
</pre></div>
<p>The size is 4 bytes written most significant byte first, being the number of
subsequent data bytes, or the twos complement negative of that when a negative
integer is represented. The data bytes are the absolute value of the integer,
written most significant byte first.
</p>
<p>The most significant data byte is always non-zero, so the output is the same
on all systems, irrespective of limb size.
</p>
<p>In GMP 1, leading zero bytes were written to pad the data bytes to a multiple
of the limb size. <code>mpz_inp_raw</code> will still accept this, for
compatibility.
</p>
<p>The use of “big endian” for both the size and data fields is deliberate, it
makes the data easy to read in a hex dump of a file. Unfortunately it also
means that the limb data must be reversed when reading or writing, so neither
a big endian nor little endian system can just read and write <code>_mp_d</code>.
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