On 16-2-2013 9:09, Sven Barth wrote: > On 15.02.2013 23:54, Mark Morgan Lloyd wrote: >> If multiple, related, programs running on unix (Linux, Solaris etc.) >> refer to the same configuration file accessed via a TIniFile, is there >> any recommended "good practice" to ensure that they don't try to update >> it simultaneously? >> >> In the case that I'm thinking of, I don't anticipate e.g. multiple >> logins trying to write setup information at the same time. The more >> risky case is if there are e.g. multiple daemons or apps trying to save >> state when a UPS signals imminent shutdown. >> > > This might be for Windows, but I think this applies here as well: > http://blogs.msdn.com/b/oldnewthing/archive/2004/11/22/267890.aspx
Security problems with world-writable files? Yes, that problem applies to *nix as well but Mark has given no indication his config files are world-writable. (Even if the logins Mark speaks of run under different user accounts, there's such a thing as groups on *nix, too :) ) UPS shutdown: no experience with that - I'd expect the process to just get a regular kill signal; perhaps the OS/UPS driver provides dbus (or other messaging layer) notifications. If the data is not that important, wouldn't a naive approach like a loop that - repeats say max 3x, - tries to save the data, - catching exceptions coming from TIniFile, then waiting a random small amount of time - giving up after those 3x help? Obviously, this problem would be alleviated if you run under multiple different accounts (normal applications) and properly save settings somewhere in the user's ~ directory rather than a systemwide path (which the FPC getconfig... forgot exactly supports). _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
