php and writing to files

[Anon]

Hello,

I'm quite new to the php world. My one question is that when I open a file using

$fp = fopen($filename, r+)

when I write to the file, am I overwriting the information that is at byte x, or am I inserting new information at byte x and moving what was in byte x to x + y. Where y is the length of the new information?

My plan is to insert the new information into the file where required. This would save on having to rewrite information into the file that is already there. Would I be better off to just overwrite the file in it's intirety??

Thanks in advance for any possible help anyone will be able to give me.

Shaun

[Anon]

You cannot insert into the middle of a file on the disk.

Open the file in r+ mode, read the entire file into memory, manipulate the data, rewind(), and write the whole file.

If your application requires a great deal of updating and insertion, you should consider whether the file is an appropriate storage solution. A database might be better, or a directory containing multiple files.