Fseek and fwrite functions HELP (newbie question)

[mcs]

Im kind of newb so if this is a newbie question, please bear with me. I have a file that i would like to fwrite() a variable into, and I am fine with that, at the bottom of the page, but I would like to write it in 490 bytes into the file, and have the rest of the content scroll down instead of being deleted. I tried this:

$add = fopen("index.htm","r+");
fseek($add, 489);
fwrite($add,stripslashes($topiclink));
fclose($add);

But it seems to delete whatever gets in its way, is there something maybe with the fopen() command that could help me out?
Thanks,
Steve

[drew010]

if you open the file for a mode of writing and you move the file pointer, it will overwrite any data that is "in the way." if you wish to insert contents into the middle of the file and have the rest move down, you will need to make your own sort of function to read the contents of the file and write your data to the middle of it.

it could be something along these lines:

$file = file_get_contents("filename.dat");

$part1 = substr($file, 0, 490);
$part2 = "what you want to insert...";
$part3 = substr($file, 491);

$fp = fopen("filename.dat", "w+");
fwrite($fp, $part1 . $part2 . $part3);
fclose($fp);

that should essentially do just what you want. work on making it a function where you can specify the filename, and the insert point and you should be good to go.

[mcs]

Thank you, that helps a little, the substr() function is new to me, I can see how it could be very usefull.
Thanks
Steve