Re: How to know if a file is finished writing or not ?

Rene Brun (Rene.Brun@cern.ch)
Mon, 06 Jul 1998 13:18:00 +0200

Wei Xie wrote:
>
> Dear Rooters'
>
> Assume I have a data file which is written on a disk, and deleted
> automatically after 5 minutes, and then written on the disk again.
> This loop will continues as long as necessary.
>
> If I want to read the file in ROOT every now and then,
> the old file may have already been deleted and new file is still being
> written and not finished yet. So if I read it at this moment, some
> errors will occur. Is there any method in ROOT that can distinguish if
> a file is finished written or not ?
>

You can test if at least one object has been written to the file
with:

TFile *myfile;
myfile = new TFile("myfile.root");
if (myfile.GetSeekKeys() <= 64) {
printf("file probably not yet closed\n");
// wait and try again
}

Note that you will get a Warning message from Root every time
you try to connect a file not yet closed.

Rene Brun