SplFileObject::fseek()

(PHP 5 >= 5.1.0, PHP 7)

Seek to a position

说明

publicSplFileObject::fseek(int $offset[,int $whence= SEEK_SET]): int

Seek to a position in the file measured in bytes from the beginning of the file, obtained by adding$offsetto the position specified by$whence.

参数

$offset

The offset. A negative value can be used to move backwards through the file which is useful when SEEK_END is used as the$whencevalue.

$whence

$whencevalues are:

SEEK_SET- Set position equal to$offsetbytes.
SEEK_CUR- Set position to current location plus$offset.
SEEK_END- Set position to end-of-file plus$offset.

If$whenceis not specified, it is assumed to be SEEK_SET.

返回值

Returns 0 if the seek was successful,-1 otherwise. Note that seeking past EOF is not considered an error.

范例

SplFileObject::fseek() example

<?php
$file = new SplFileObject("somefile.txt");
// Read first line
$data = $file->fgets();
// Move back to the beginning of the file
// Same as $file->rewind();
$file->fseek(0);
?>

参见

fseek()在文件指针中定位