The fflush() function in PHP is an inbuilt function which is used to write all the buffered output to an open file. The fflush() function forces a write of all buffered output to the resource pointed to by the file handle. The fflush() function returns true on success and false on failure.
Syntax:
fflush($file)
Parameters: The fflush() function in PHP accepts only one parameter which is $file. It specifies the open file stream.
Return Value: It returns TRUE on success and FALSE on failure.
Errors And Exception:
- The fflush() function results in errors if the file pointer is not valid.
- The file pointed must be opened by fopen() or fsockopen() and closed by fclose().
Below programs illustrate the fflush() function.
Program 1: In the below program the file named singleline.txt contains a single line of information which is “This file consists of a single line.”.
<?php // The file is opened using fopen() function $check = fopen("singleline.txt", "r"); $seq = fgets($check); // Writing buffered output to a file // until the end-of-file is reached while(! feof($check)) fflush($check); // The file is closed using fclose() function fclose($check); ?> |
Output:
This file consists of a single line.
Program 2: In the below program the file named gfg.txt contains the following piece of text.
This is the first line.
This is the second line.
This is the third line.
<?php // The file is opened using fopen() function $check = fopen("gfg.txt", "r"); $seq = fgets($check); // Writing buffered output to a file // until the end-of-file is reached while(! feof($check)) fflush($check); // The file is closed using fclose() function fclose($check); ?> |
Output:
This is the first line. This is the second line. This is the third line.
Reference:
http://php.net/manual/en/function.fflush.php
