PureBasic Forums - English

would be nice to have a flag for OpenFile to open files with nonexclusive write access.
this would enable us to write our own multi-access database systems.

http://www.purebasic.fr/english/viewtop ... 13&t=41273

#PB_File_NonExclusive = -1
#PB_File_Exclusive = 0

OpenFile(#File, FileName$ [, AccessFlag = #PB_File_Exclusive ] )

Doesn't write access require exclusive access? ReadFile won't lock it, I think. It's only when you want to open a file for writing more than once that it locks.

I haven't tried it so I'm talking off the top of my head. But this is how I think it works.

this is correct, that's how it is now.
I don't know if it is even possible to grant multiple write access.
but if it was possible, I wish we could use it.
if the OS would not allow it, this request is pointless and can be closed.

I use this all the time with my web browser when downloading mp3 files. I open them in Winamp before they are completely downloaded. So this is definetely possible.
Also this is one of the reasons I really HATE Firefox, it gives downloaded files a different file extension until they are completely downloaded, when it renames them. Of course this makes it inconvenient to open them in the correct program in the first place, and when the download is completed you have to open them again.

Trond wrote:it gives downloaded files a different file extension until they are completely downloaded

That's a safety feature. If you open an incomplete file, it can cause buffer overflows and other problems. I recall seeing that as an Internet Explorer exploit, which is just another reason why FF is safer than IE.

Kaeru Gaman wrote:this is correct, that's how it is now.
I don't know if it is even possible to grant multiple write access.
but if it was possible, I wish we could use it.
if the OS would not allow it, this request is pointless and can be closed.

It is possible under Windows, no problem. Just not with PureBasic's OpenFile().