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Mimo, że strony WWW tworzymy już 5 lat zawsze znajdziemy coś ciekawego. Świadczy o tym chociażby nasza aktówka, w której znajduje się kilkadziesiąt porad, z których często korzystamy. Otwarta forma poradnika, czyli możliwość podrzucania tematów oraz wspólny ich rozwój, to nieoceniona pomoc. Uważam, ze abonament roczny jest niewspółmiernie niski do jakości zaprezentowanych materiałów.
Marek Kończal
Internetix.pl
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PODRĘCZNIK PHP 5.x, 4.x, 3.x - częściowo spolszczony / źródło: www.php.net
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ftruncate (PHP 4, PHP 5) ftruncate -- Przycina plik do podanej długości Opisbool ftruncate ( resource uchwyt, int rozmiar )
Pobiera wskaźnik pliku, uchwyt i przycina plik do długości,
rozmiar. Zwraca TRUE w przypadku sukcesu, FALSE w
przypadku porażki.
Notatka:
Przed PHP 4.3.3, ftruncate() zwracała
integer o wartości 1 w przypadku sukcesu, zamiast
boolean TRUE.
Patrz także: fopen() i
fseek().
User Contributed Noteslatet at poczta dot onet dot pl
13-Aug-2004 08:01
I want to report:
on Apache/2.0.48 (Linux/SuSE), PHP Version 4.3.3.
It is very different in "a" and in "r" modes.
After fopen in "a" mode, I don't have to fseek before ftruncate ($fp, 0) and even between ftruncate and the following fputs (if I need to write to the begining of the file).
But if I open in "r" mode and read some bytes, and then I want to ftruncate ($fp, 0) and write again - I do need to put fseek($fp, 0); just after ftruncate ($fp, 0).
Latet
rc at opelgt dot org
12-May-2004 03:35
I was confused by the different fopen modes (r, r+, w, w+, a, a+).
I wrote
<?php
$alt = '1234567890';
$neu = '13579';
$datei = 'test.txt';
$dh = fopen ($datei,"w");
fwrite($dh, $alt);
fclose($dh);
$dh = fopen ($datei,"a+"); rewind($dh);
echo "Inhalt<BR>\nalt: ".fread($dh, filesize($datei))."<BR>\n";
ftruncate($dh, '0');
fwrite($dh, $neu);
rewind($dh);
echo 'neu: '.fread($dh, filesize($datei));
fclose($dh);
?>
to find out what happens:
1. For me ftruncate to a size of 0 takes the pointer to position 0 successfully. Tested under UNIX with PHP 4.2.3 and under MacOSX 10.3 with PHP 4.3.4
2. Writing to a file opened with 'a' or 'a+' always begins writing at the end of the file. A rewind before doesnt help! ('a' for always append!)
macrudi
stevedegrace von yahoo point ca
16-Nov-2003 11:07
I am using PHP 4.3.2 and I can confim you do need to seek to the beginning of the file before truncating and writing. I found that failing to rewind before truncating and writing caused my output file to be uninterpretable by some applications, but by rewinding first the desired result was achieved.
jfb
05-Sep-2003 12:30
> ftruncate does not alter the position of the file pointer
Are you sure ? On linux with PHP 4.2.2 there is no problem if I don't seek to the beginning of the file before writing.
jim dot hatfield at insignia dot com
15-Jun-2001 03:58
ftruncate does not alter the position of the file pointer. If you edit a file in-place by opening for reading and writing, reading the file, truncating and writing out again, you have to seek to the beginning before writing or you get as many NULLs as there were bytes in the original file, then your new content.
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