How to get number of referenced fd??

[Herbert Simon]

Hello!

I want to know how many processes have a reference via open() to a given file. This file can be resist in an NFS-share or local.
I know that there must be a conter for that but i don't know how to access it..
Anybody for a good idea??

Thanks a lot!

Karsten

[Steve Steel]

Hi

go to

http://hpux.connect.org.uk/

look at lsof and libevent-0.4

Ths sources should help

Steve Steel

[Stephen Keane]

and don't forget to assign points to those that have helped you.

[Herbert Simon]

Hi, Thanks for your help.

lsof is verry mighty and total overdone for my (simple) request. To parse the source ( ~ 80.000 lines ) to get the necessary information is a little bit to hard for me :-)

Karsten

[Peter Godron]

Herbert,
another method would be to use fcntl() with the f_getlk parameter to search for the lock on the file.
Using the l_type and l_pid from the flock structure would give you the process id.
Regards

[Gordon Morrison]

Have you tried

fuser filename

?

[Herbert Simon]

Hi Peter!

Well, F_GETLCK don't helps if the other process do not do a lock to the file. I played with this solution but i don't want to use file locks over NFS ( NEVER do this.. expactly with HP :-( we have a lot of verry bad experiences with it)
At least I need a save( realy save ) way to synchronise a process after a file is fully written by a external process ( 3D Application ) without lost seconds to wait if mtime/ctime isn't more changed.The write can take a lot of seconds ( big files over NFS which runs over smal leased Lines). The idea is to check the number of open references ( filedescriptors ) to this file. If it is zero
i know the write is done.

regards
Karsten

[Gordon Morrison]

WOOHOO!
I got a hat!
:oD