Dear Experts, I'm hoping that your experience with SMB and CIFS means that you're familiar with cross-platform file locking. I need a lowest-common-denominator whole-file locking method that will work on as many combinations of client and server systems as possible; in particular it needs to run on - Linux client talking to NFS server. - Linux client talking to Samba server. - Linux client talking to Windows server. - Windows client talking to Samba server. - Windows client talking to Windows server. - Linux local disk access. - Windows local disk access. No doubt each of those combinations has many variations. I only need advisory locking, not mandatory locking; a lockfile convention would be fine. I'm hoping that something like the algorithm used by liblockfile could be used (see man lockfile_create, e.g. pwet.fr/man/linux/fonctions_bibliotheques/lockfile_create). Basically it creates a file with a unique name, links it to the <filename>.lock file, and uses stat() to see if its link got there before any other contender. This is designed to be NFS-safe but I don't know if it would be possible or safe in an SMB or CIFS environment. I'm sure this must have been solved before but I can't find anything especially helpful; maybe I'm not searching for the right keywords. If anyone can point me in the right direction I would be very grateful. Regards, Phil.