What does feof mean in PHP?

feof in PHP is a function used to detect whether the end of a file has been reached. Its usage syntax is "feof(file)", where the parameter file specifies the open file to be checked.

#The operating environment of this article: Windows7 system, PHP7.1, Dell G3 computer.

What does feof mean in PHP?

feof() function detects whether the end of file (eof) has been reached.

If the file pointer reaches EOF or an error occurs, TRUE is returned, otherwise an error (including socket timeout) is returned, and FALSE is returned in other cases.

Syntax

feof(file)

Parameters

file required. Specifies the open file to be checked.

Description

The file parameter is a file pointer. This file pointer must be valid and must point to a file that was successfully opened by fopen() or fsockopen() (but has not been closed by fclose()).

Tips and Notes

Tip: The feof() function is useful for traversing data of unknown length.

Note: If the server does not close the connection opened by fsockopen(), feof() will wait until timeout and return TRUE. The default timeout limit is 60 seconds, this value can be changed using stream_set_timeout().

Note: If the passed file pointer is invalid, it may fall into an infinite loop, because EOF will not return TRUE.

Example

<?php
$file = fopen("test.txt", "r");
//输出文本中所有的行，直到文件结束为止。
while(! feof($file))
  {
  echo fgets($file). "<br />";
  }
fclose($file);
?>

Output:

Hello, this is a test file. 
There are three lines here. 
This is the last line.

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