fclose
Johannes: Remember note from stream_get_meta_data page: For socket streams this member [eof] can be TRUE even when unread_bytes is non-zero. To determine if there is more data to be read, use feof() instead of reading this item.
Another thing: better not rely on the "including socket timeout" part of when feof returns true. Just found program looping two days in while(!feof($fd)) fread ... with 20 seconds timeout in PHP 4.3.10.
feof
(PHP 4, PHP 5)
feof — Sprawdza czy wskaźnik pliku jest na końcu pliku (EOF)
Opis
bool feof
( resource $uchwyt
)
Sprawdza czy wskaźnik pliku jest na końcu pliku (EOF).
Parametry
- uchwyt
-
Wskaźnik na plik musi być poprawny i musi wskazywać na plik pomyślnie otwarty przez funkcję fopen() lub fsockopen() (a jednocześnie nie zamknięty jeszcze przez fclose()).
Zwracane wartości
Zwraca TRUE jeśli wskaźnik pliku jest na EOF lub gdy zdarzy się błąd (także timeout połączena socket'owego);w przeciwnym wypadku zwraca FALSE.
Notatki
Ostrzeżenie
Jeśli połączenie otworzone za pomocą fsockopen() nie zostanie zamknięte przez serwer, feof() będzie czekać aż timeout zostanie osiągniety, wtedy zwróci TRUE. Domyślny timeout to 60 sekund. Możesz użyć stream_set_timeout() aby zmienić tą wartość.
Ostrzeżenie
Jeśli podano nieprawidłowy wskaźnik pliku to możesz uzyskać nieskończoną pętle, ponieważ EOF w przypadku błędu zwraca TRUE.
Example #1 feof() przykład z nieprawidłowym wskaźnikiem pliku
<?php
// jeśli plik nie może zostać odczytany lub nie istnieje funkcja fopen zwróci FALSE
$file = @fopen("nie_isniejacy_plik", "r");
// FALSE z fopen spowoduje ostrzeżenie oraz wystąpi tu nieskończona pętla
while (!feof($file)) {
}
fclose($file);
?>
add a note
User Contributed Notesfeof
honzam+php at ipdgroup dot com
28-Feb-2008 11:17
28-Feb-2008 11:17
Jet
19-Sep-2007 04:03
19-Sep-2007 04:03
To avoid infinite loop with fgets() just use do..while statement.
<?php
if ($f = fopen('myfile.txt', 'r')) do {
$line = fgets($f);
// do any stuff here...
} while (!feof($f));
fclose($f);
cmr at forestfactory dot de
19-Nov-2006 05:57
19-Nov-2006 05:57
Here's solution 3:
<?
$fp = fopen("myfile.txt", "r");
while ( ($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:
<?
$fp = fopen("myfile.txt", "r");
while ( $current_line = fgets($fp) ) {
// do stuff to the current line here
}
fclose($fp);
?>
Tom
25-Oct-2006 12:27
25-Oct-2006 12:27
feof() is, in fact, reliable. However, you have to use it carefully in conjunction with fgets(). A common (but incorrect) approach is to try something like this:
<?
$fp = fopen("myfile.txt", "r");
while (!feof($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);
?>
FYI, the eof() function in C++ works the exact same way, so this isn't just some weird PHP thing...
ironoxid at libero dot it
06-Jun-2006 03:52
06-Jun-2006 03:52
I really thought that the feof() was TRUE when the logical file pointer is a EOF.
but no !
we need to read and get an empty record before the eof() reports TRUE.
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.
Sorry for my bad english.
Bye ;)
m a p o p a at g m a i l. c o m
03-Jun-2006 02:58
03-Jun-2006 02:58
you can avoid the infinite loop and filling the error logs
by an simple if statement
Here is the example
$handle = fopen("http://xml.weather.yahoo.com/forecastrss?p=AYXX0008&u=f", "r");
$xml = "";
if ($handle)
{
while (!feof($handle))
{
$xml .= fread($handle, 128);
}
fclose($handle);
}
02-Jan-2006 03:27
if you use fseek function to pos the pointer exceed the size the file,feof still return true.so note that when you use feof as the condition of while loop.
01-Aug-2005 07:21
if you hit an feof() infinite loop, watch out for resultant humongous logs, they can cripple a site with hard disk usage limits or run up excess usage fees.
04-Mar-2005 06:02
if you're worried the file pointer is invalid, TEST IT before you go into your loop... that way it'll never be an infinite loop.
Johannes
12-Mar-2004 11:47
12-Mar-2004 11:47
I found feof() to be a slow function when using a non-blocking connection.
The function stream_get_meta_data() returns much quicker and has a return field 'eof'.