fstat
When opening a file to append via fopen('file','ab') the file pointer should be at the end of the file. However ftell() returns int(0) even if the file is not empty and even after writing some text into the file.
ftell
(PHP 4, PHP 5)
ftell — ファイルの読み書き用ポインタの現在位置を返す
説明
int ftell
( resource $handle
)
handle ファイルの読み書き用ポインタの現在位置を返します。
パラメータ
- handle
-
ファイルポインタは有効なものでなければならず、また fopen()、popen() で正常にオープンされたファイルを指している必要があります。 ftell() は、("a" フラグ付きでオープンされた) 追加のみ可能なストリームに対する結果も未定義です。
返り値
handle が示すファイルポインタの位置、 すなわちファイル・ストリーム上のオフセットを整数値で返します。
エラーが起こった場合 FALSE を返します。
例
例1 ftell() の例
<?php
// ファイルをオープンし、データを読み込む
$fp = fopen("/etc/passwd", "r");
$data = fgets($fp, 12);
// どこにいるんだ ?
echo ftell($fp); // 11
fclose($fp);
?>
add a note
User Contributed Notesftell
burninleo at gmx dot net
07-Sep-2009 08:38
07-Sep-2009 08:38
missilesilo at gmail dot com
27-Feb-2007 11:02
27-Feb-2007 11:02
In response to php at michielvleugel dot com:
This does not seem to be the case with PHP 5.2.0 and FreeBSD 5.4.
#!/usr/local/bin/php
<?php
$tell = ftell(STDIN);
var_dump($tell);
?>
root@localhost:/home/david# echo Hello World | ./test.php
int(0)
root@localhost:/home/david# ./test.php
int(6629927)
When something is piped to the script, it returns an integer value of 0, however, it also returns an integer when nothing is piped to the script.
The code should be modified to this:
#!/usr/local/bin/php
<?php
$tell = ftell(STDIN);
if ($tell === 0)
echo "Something was piped: " . fread(STDIN,256) . "\n";
else
echo "Nothing was piped\n";
?>
And the result is:
root@localhost:/home/david# echo Hello World | ./test.php
Something was piped: Hello World
root@localhost:/home/david# ./test.php
Nothing was piped
mbirth at webwriters dot de
21-Oct-2005 06:09
21-Oct-2005 06:09
Attention! If you open a file with the "text"-modifier (e.g. 'rt') and the file contains \r\n as line-endings, ftell() returns the position as if there were only \n as line-endings.
Example:
If the first line only contains 1 char followed by \r\n, the start of the second line should be position 3. (1char + \r + \n = 3 bytes) But ftell() will return 2 - ignoring one byte. If you call ftell() in line 3, the value will differ from the real value by 2 bytes. The error gets greater with every line.
(Watched this behavior in PHP 5.0.4 for Windows.)
BUT: fseek() works as expected - using the true byte values.
mweierophinney at gmail dot com
21-Jun-2005 05:00
21-Jun-2005 05:00
Actually, ftell() gives more than an undefined result for append only streams; it gives the offset from the end of the file as defined before any data was appended. So if you open a file that had 3017 characters, and append 41 characters, and then execute ftell(), the value returned will be 41.
php at michielvleugel dot com
01-Jun-2005 10:19
01-Jun-2005 10:19
When trying to determine whether or not something was piped into a command line script, it is not smart to do a fgets(STDIN), because it will wait indefenitely if nothing is piped. Instead, I found ftell on STDIN to be very handy: it will return an integer of zero when something was piped, and nothing if nothing was piped to the script.
#!/usr/bin/php4 -q
<?
#following will hang if nothing is piped:
#$sometext = fgets(STDIN, 256)
$tell = ftell(STDIN);
if (is_integer($tell)==true)
{echo "Something was piped: ".fread(STDIN,256)."\n";}
else
{echo "Nothing was piped\n";}
?>