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);
?>
feof
(PHP 4, PHP 5)
feof — ファイルポインタがファイル終端に達しているかどうか調べる
説明
bool feof ( resource $handle )ファイルポインタが EOF に達しているかまたはエラー (ソケットタイムアウトを含みます) の場合に TRUE 、 その他の場合に FALSE を返します。
警告
もし fsockopen() でオープンされた接続がサーバによって 閉じられていない場合、feof() はタイムアウトになるまで待ち、TRUE を返します。 デフォルトのタイムアウト値は 60 秒です。この値を変更するには stream_set_timeout() を使用します。
ファイルポインタは、有効なファイルポインタである必要があり、 fopen() または fsockopen() で正常にオープンされた （そしてまだ fclose() でクローズされていない） ファイルを指している必要があります。
feof
cmr at forestfactory dot de
20-Nov-2006 01:57
20-Nov-2006 01:57
Tom
25-Oct-2006 07:27
25-Oct-2006 07:27
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 10:52
06-Jun-2006 10:52
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 09:58
03-Jun-2006 09:58
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 11:27
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 02:21
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.
05-Mar-2005 02:02
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 07:47
12-Mar-2004 07:47
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'.