return feof($fp);
}

/* $fp 的赋值是由之前 fsockopen() 打开  */

$start = NULL;
$timeout = ini_get(‘default_socket_timeout‘);

// 来自 fopen 的 FALSE 会发出一条警告信息并在这里陷入无限循环
while (!feof($file)) {
}

NOTE: I used ";" to denote the end of data transmission.  This can be modified to whatever the server‘s end of file or in this case, end of output character is.

<?php
        $cursor = "";
        $inData = "";

while(strcmp($cursor, ";") != 0) {
            $cursor = fgetc($sock);
            $inData.= $cursor;
        }
        fclose($sock);
        echo($inData);
?>

Since strcmp() returns 0 when the two strings are equal, it will return non zero as long as the cursor is not ";".  Using the above method will add ";" to the string, but the fix for this is simple.

<?php
        $cursor = "";
        $inData = "";

$cursor = fgetc($sock);
        while(strcmp($cursor, ";") != 0) {
            $inData.= $cursor;
        }
        fclose($sock);
        echo($inData);
?>

So

$fp = fopen(‘test.bin‘,‘rb‘);
while(!feof($fp)) {
  $c = fgetc($fp);
  // ... do something with $c 
  echo ftell($fp), ",";
}
echo ‘EOF!‘;

prints for two time the last byte position.
If our file length is 5 byte this code prints

0,1,2,3,4,5,5,EOF!

Because of this, you have to do another check to verify if fgetc really reads another byte (to prevent error on "do something with $c" ^_^).

To prevent errors you have to use this code

$fp = fopen(‘test.bin‘,‘rb‘);
while(!feof($fp)) {
  $c = fgetc($fp);
  if($c === false) break;
  // ... do something with $c 
}

but this is the same of

$fp = fopen(‘test.bin‘,‘rb‘);
while(($c = fgetc($fp))!==false) {
  // ... do something with $c 
}

Consequently feof() is simply useless.
Before write this note I want to submit this as a php bug but one php developer said that this does not imply a bug in PHP itself (http://bugs.php.net/bug.php?id=35136&edit=2).

If this is not a bug I think that this need at least to be noticed.

<?
$fp = fopen("myfile.txt", "r");
while (!feof($fp)) {
  $current_line = fgets($fp);
  // do stuff to the current line here
}
fclose($fp);
?>

The problem when processing plain text files is that feof() will not return true after getting the last line of input.  You need to try to get input _and fail_ before feof() returns true.  You can think of the loop above working like this:

* (merrily looping, getting lines and processing them)
* fgets used to get 2nd to last line
* line is processed
* loop back up -- feof returns false, so do the steps inside the loop
* fgets used to get last line
* line is processed
* loop back up -- since the last call to fgets worked (you got the last line), feof still returns false, so you do the steps inside the loop again
* fgets used to try to get another line (but there‘s nothing there!)
* your code doesn‘t realize this, and tries to process this non-existent line (typically by doing the same actions again)
* now when your code loops back up, feof returns true, and your loop ends

There‘s two ways to solve this:

1. You can put an additional test for feof() inside the loop
2. You can move around your calls to fgets() so that the testing of feof() happens in a better location

Here‘s solution 1:

<?
$fp = fopen("myfile.txt", "r");
while(!feof($fp)) {
  $current_line = fgets($fp);
  if (!feof($fp)) {
    // process current line
  }
}
fclose($fp);
?>

And here‘s solution 2 (IMHO, more elegant):

<?
$fp = fopen("myfile.txt", "r");
$current_line = fgets($fp);
while (!feof($fp)) {
  // process current line
  $current_line = fgets($fp);
}
fclose($fp);
?>

<?
$fp = fopen("myfile.txt", "r");
while ( ($current_line = fgets($fp)) !== false ) {
  // do stuff to the current line here
}
fclose($fp);
?>

AFAICS fgets() never returns an empty string, so we can also write:

Returns TRUE if the file pointer is at EOF or an error occurs (including socket timeout); otherwise returns FALSE.

Correct text would be more like:

Returns FALSE if no filehandle was passed; 
returns NULL if no filehandle was passed; 
returns TRUE if the file pointer is at EOF or an error occurs (including socket timeout);
otherwise returns FALSE.

As an example, running the following from the commandline:

php -r ‘echo 
    "Empty: ".var_export(feof(), true)."\n".
    "Null: ".var_export(feof(NULL), true)."\n".
    "Undefined: ".var_export(feof($undef), true)."\n"
;‘

This will output:

PHP Warning:  Wrong parameter count for feof() in Command line code on line 1
PHP Warning:  feof(): supplied argument is not a valid stream resource in Command line code on line 1
PHP Warning:  feof(): supplied argument is not a valid stream resource in Command line code on line 1

Empty: NULL
Null: false
Undefined: false