fseek()

fseek() — Seeks on a file pointer.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Sets the file position indicator for the file referenced by stream. The new position, measured in bytes from the beginning of the file, is obtained by adding offset to the position specified by whence.

Signature

fseek(resource $stream, int $offset, int $whence = SEEK_SET): int

Parameters

Parameter	Type	What it takes
$stream	resource	A file system pointer resource that is typically created using fopen().
$offset	int	The offset.
$whence	int	whence values are: SEEK_SET - Set position equal to offset bytes from the start of the file. SEEK_CUR - Set position to current location plus offset bytes. SEEK_END - Set position to end-of-file plus offset bytes.

Return value

Upon success, returns 0; otherwise, returns -1. This function was created to imitate the C language function of the same name. Please pay attention to the return values as they differ from what one would expect in PHP.

Example

A runnable snippet:

$fp = fopen('somefile.txt', 'r'); // read some data $data = fgets($fp, 4096); // move back to the beginning of the file // same as rewind($fp); fseek($fp, 0);