The default value for $whence is OCI_SEEK_SET.
(PHP 5, PHP 7, PECL OCI8 >= 1.1.0)
OCI-Lob::seek — Sets the internal pointer of the large object
$offset
[, int $whence = OCI_SEEK_SET
] ) : boolSets the internal pointer of the large object.
offset
Indicates the amount of bytes, on which internal pointer should be
moved from the position, pointed by whence.
whenceMay be one of:
OCI_SEEK_SET - sets the position equal to
offset
OCI_SEEK_CUR - adds offset
bytes to the current position
OCI_SEEK_END - adds offset
bytes to the end of large object (use negative value to move to a position
before the end of large object)
成功时返回 TRUE， 或者在失败时返回 FALSE。
The default value for $whence is OCI_SEEK_SET.