Re: #pragma once in ISO standard yet?
On Dec 17, 7:05 pm, Andre Kaufmann <akfmn...@t-online.de> wrote:
James Kanze wrote:
Well, what I really want to say that it's just typical for
C++. Header files should be included only once in 99,9999%.
Why do I have to protect the header files with include guards
or even with #pragma once ?
Because there's no other technical solution.
That's not really true, of course. Modula-2 did it, and so does
Ada. But in a far different context, with a somewhat different
compilation model. It doesn't work with the current compilation
model of C++, and you can't eliminate that. It's possible to
provide an alternative, of course, and there is a proposal for
modules being considered. But to make it work, you need to go
far beyond simply "#pragma once".
It feels unnatural for me using >macros< to accomplish that.
For me that's just a workaround I have to use because there's
no other solution.
I don't think anyone would deny that. It's a hack.
[...]
For local files, I don't think it's a problem. But I can't
remember the last time I compiled against libraries on a local
disk professionally. (Even at home, when I compile under
Windows, the sources are generally remote mounted on my Linux
server. Trying to keep even two copies in sync is just an
unnecessary complication.)
Well the synchronization is done by the source revision system
automatically and my hard disk is still way faster than the
network I'm using.
I've never seen a system where the synchronization actually
worked reliably, other than with Clearcase, which uses a file
server model. And of course, other machines can't read your
local disk. What happens when you do a complete rebuild, where
the compiles are distributed through out the network? What
happens when you want to discuss something with a collegue, at
his desk?
Nothing which you are actually working on should ever be on a
local disk; if you're working on it, you must be able to access
your current, working version, from all of the machines on the
network.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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