Sets the file position indicator for the file referenced by fp.The new position, measured in bytes from the beginning of the file, is obtained by adding offset to the position specified by whence, whose values are defined as follows:
| SEEK_SET - Set position equal to offset bytes. |
| SEEK_CUR - Set position to current location plus offset. |
| SEEK_END - Set position to end-of-file plus offset. (To move to a position before the end-of-file, you need to pass a negative value in offset.) |
If whence is not specified, it is assumed to be SEEK_SET.
Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error.
May not be used on file pointers returned by fopen() if they use the "http://" or "ftp://" formats.
Note: The whence argument was added after PHP 4.0.0.