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<a href="intro.html"><h2>Session Module C Interface</h2></a><h2>Create An Iterator To Traverse A Changeset </h2><blockquote><pre>int sqlite3changeset_start(
  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
  int nChangeset,                 /* Size of changeset blob in bytes */
  void *pChangeset                /* Pointer to blob containing changeset */
);
int sqlite3changeset_start_v2(
  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
  int nChangeset,                 /* Size of changeset blob in bytes */
  void *pChangeset,               /* Pointer to blob containing changeset */
  int flags                       /* SESSION_CHANGESETSTART_* flags */
);
</pre></blockquote><p>
Create an iterator used to iterate through the contents of a changeset.
If successful, *pp is set to point to the iterator handle and SQLITE_OK
is returned. Otherwise, if an error occurs, *pp is set to zero and an
SQLite error code is returned.</p>

<p>The following functions can be used to advance and query a changeset 
iterator created by this function:</p>

<p><ul>
  <li> <a href="../session/sqlite3changeset_next.html">sqlite3changeset_next()</a>
  <li> <a href="../session/sqlite3changeset_op.html">sqlite3changeset_op()</a>
  <li> <a href="../session/sqlite3changeset_new.html">sqlite3changeset_new()</a>
  <li> <a href="../session/sqlite3changeset_old.html">sqlite3changeset_old()</a>
</ul></p>

<p>It is the responsibility of the caller to eventually destroy the iterator
by passing it to <a href="../session/sqlite3changeset_finalize.html">sqlite3changeset_finalize()</a>. The buffer containing the
changeset (pChangeset) must remain valid until after the iterator is
destroyed.</p>

<p>Assuming the changeset blob was created by one of the
<a href="../session/sqlite3session_changeset.html">sqlite3session_changeset()</a>, <a href="../session/sqlite3changeset_concat.html">sqlite3changeset_concat()</a> or
<a href="../session/sqlite3changeset_invert.html">sqlite3changeset_invert()</a> functions, all changes within the changeset 
that apply to a single table are grouped together. This means that when 
an application iterates through a changeset using an iterator created by 
this function, all changes that relate to a single table are visited 
consecutively. There is no chance that the iterator will visit a change 
the applies to table X, then one for table Y, and then later on visit 
another change for table X.</p>

<p>The behavior of sqlite3changeset_start_v2() and its streaming equivalent
may be modified by passing a combination of
<a href="../session/c_changesetstart_invert.html">supported flags</a> as the 4th parameter.</p>

<p>Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
and therefore subject to change.
</p><p>See also lists of
  <a href="objlist.html">Objects</a>,
  <a href="constlist.html">Constants</a>, and
  <a href="funclist.html">Functions</a>.</p>