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<a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Read Data From A BLOB Incrementally</h2><blockquote><pre>int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
</pre></blockquote><p>
This function is used to read data from an open <a href="../c3ref/blob.html">BLOB handle</a> into a
caller-supplied buffer. N bytes of data are copied into buffer Z
from the open BLOB, starting at offset iOffset.</p>
<p>If offset iOffset is less than N bytes from the end of the BLOB,
<a href="../rescode.html#error">SQLITE_ERROR</a> is returned and no data is read. If N or iOffset is
less than zero, <a href="../rescode.html#error">SQLITE_ERROR</a> is returned and no data is read.
The size of the blob (and hence the maximum value of N+iOffset)
can be determined using the <a href="../c3ref/blob_bytes.html">sqlite3_blob_bytes()</a> interface.</p>
<p>An attempt to read from an expired <a href="../c3ref/blob.html">BLOB handle</a> fails with an
error code of <a href="../rescode.html#abort">SQLITE_ABORT</a>.</p>
<p>On success, sqlite3_blob_read() returns SQLITE_OK.
Otherwise, an <a href="../rescode.html">error code</a> or an <a href="../rescode.html#extrc">extended error code</a> is returned.</p>
<p>This routine only works on a <a href="../c3ref/blob.html">BLOB handle</a> which has been created
by a prior successful call to <a href="../c3ref/blob_open.html">sqlite3_blob_open()</a> and which has not
been closed by <a href="../c3ref/blob_close.html">sqlite3_blob_close()</a>. Passing any other pointer in
to this routine results in undefined and probably undesirable behavior.</p>
<p>See also: <a href="../c3ref/blob_write.html">sqlite3_blob_write()</a>.
</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>
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