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Re: Posix Inter-process comunication on RH 7.1




On Thu, 25 Oct 2001, Gold Edward wrote:

> 1. About Posix compliance I think the same as you-- so I'm still waiting
> for some answer on that.

the term 'POSIX compliance' is very fluid. even windows NT 4.0 was
marketed as 'POSIX compliant'. one rather should state 'this system is
POSIX.1 compliant', 'that system is also POSIX.2b compliant', etc.

one of the reasons for its fluidness is that parts of it are optional.
also, the standard changes all the time (mostly having new additions) so
at a given moment, there are hardly any fully compliant systems (cause
they didnd't yet implement a new part of the standard that was just
accepted, for instance) - and the only way to solve this, is making new
parts optional.

also, in some parts ot the standard, there are optional features, causing
the implementations across OSes to be non-portable (e.g. there are
optional functions, which only some OSes implement. if you use them - you
find it hard to port programs).

for this reason, it is always a good idea not to rely on POSIX directly,
and rather use some portability libraries - hoping that the writer of the
library will port it ao all OSes you might need to run your software on in
the future, or hopeing the library is open source, and that you'll be able
to do the port to a new platform yourself, if the need arises (its
soemtimes cheaper to do that, then to be unable to port to a new platform,
in terms of losing contracts).

btw, if you search the web, you'll find various attempts of making kernel
patches to support various parts of POSIX* standards - i've no idea how
stable these things are, or whether they are maintained to work on newer
kernels.

--
guy

"For world domination - press 1,
 or dial 0, and please hold, for the creator." -- nob o. dy


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