SplFileObject::fseek()
(PHP 5 >= 5.1.0, PHP 7)
Seek to a position
说明
public SplFileObject::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