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<a href="../c3ref/intro.html"><h2>SQLite C Interface</h2></a>
<h2>Compare the ages of two snapshot handles.</h2>
</div>
<blockquote><pre>
int sqlite3_snapshot_cmp(
sqlite3_snapshot *p1,
sqlite3_snapshot *p2
);
</pre></blockquote>
<p>
The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
of two valid snapshot handles.</p>
<p>If the two snapshot handles are not associated with the same database
file, the result of the comparison is undefined.</p>
<p>Additionally, the result of the comparison is only valid if both of the
snapshot handles were obtained by calling sqlite3_snapshot_get() since the
last time the wal file was deleted. The wal file is deleted when the
database is changed back to rollback mode or when the number of database
clients drops to zero. If either snapshot handle was obtained before the
wal file was last deleted, the value returned by this function
is undefined.</p>
<p>Otherwise, this API returns a negative value if P1 refers to an older
snapshot than P2, zero if the two handles refer to the same database
snapshot, and a positive value if P1 is a newer snapshot than P2.</p>
<p>This interface is only available if SQLite is compiled with the
<a href="../compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> option.
</p><p>See also lists of
<a href="../c3ref/objlist.html">Objects</a>,
<a href="../c3ref/constlist.html">Constants</a>, and
<a href="../c3ref/funclist.html">Functions</a>.</p>
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