PHP Tutorial - PHP fseek() Function

Definition

The fseek() function seeks in an open file, by moving the file pointer from its current position to a new position, forward or backward, specified by the number of bytes.

Syntax

PHP fseek() Function has the following syntax.

fseek(file,offset,whence)

Parameter

Parameter	Is Required	Description
file	Required.	Open file to seek in
offset	Required.	New position (measured in bytes from the beginning of the file)
whence	Optional.	Option

Possible values for whence:

SEEK_SET - Set position equal to offset. Default
SEEK_CUR - Set position to current location plus offset
SEEK_END - Set position to EOF plus offset to move to a position before EOF, the offset must be a negative value

Return

This function returns 0 on success, or -1 on failure. Seeking past EOF will not generate an error.

Example

fseek() moves a file handle pointer to an arbitrary position.


<?PHP// ww  w.  j av  a2s . c  o  m
      $filename = "c:/abc/test.txt";
      $handle = fopen($filename, "w+");
      fwrite($handle, "java2s.com\n");
      rewind($handle);
      fseek($handle, 1);
      fwrite($handle, "o");
      fseek($handle, 2, SEEK_CUR);
      fwrite($handle, "e");
      fclose($handle);
?>

The first byte of a file is byte 0, and you count upward from there. The second byte is at index 1, the third at index 2, etc.

Find the current position by using ftell().