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<! "@(#)h_hash.so 10.1 (Sleepycat) 10/20/98">
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<title>Berkeley DB Reference Guide: Access Methods</title>
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<h3>Berkeley DB Reference Guide: Access Methods</h3>
<p>
<h1 align=center>Specifying your own hashing function (h_hash)</h1>
<p>
The hash function for the hash table can be specified as part of the
<a href="../../api_c/Db/open.html">db_open</a> call to open the database, specifically by setting the
<a href="../../api_c/DbInfo/info.html#h_hash">h_hash</a> element of the DB_INFO structure. If no
hash function is specified, a default function will be used.
<p>
Since no hash function performs equally well on all possible data,
it is possible that applications may find that the default hash function
performs poorly with a particular data set.
<p>
Any application-specified hash function must take a pointer to a byte
string and a length as arguments and return an unsigned, 32-bit hash
value.
<p>
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