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Re: Macro does not work in source code.

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Jorgen Grahn <grahn+nntp@snipabacken.se> writes:

> On Sat, 2011-07-30, MJ_India wrote:
>> On Jul 29, 9:36 am, Nephi Immortal <immortalne...@gmail.com> wrote:
>
>> [Prefer to use #pragma once instead of ifndef guards]
>
> That last sentence -- is that supposed to be an advice? I've never
> seen anything other than the include guard stuff you described above.
> And my compiler (g++) doesn't seem to have a pragma named "once".

It's a Microsoft Visual-C++ thing, it means the header should only be
opened and read once. It's effectively equivalent to include guards and
may speed up compiles as long as you know your code is and will always
be VC++ specific (it depends on other Microsoft-isms), or if you
don't care that your code will only compile efficiently with Visual C++.

I suppose you could use both, and get the MS speed tweak and
portability.

--
Brian

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Thread

Macro does not work in source code. Nephi Immortal <immortalnephi@gmail.com> - 2011-07-28 17:36 -0700
  Re: Macro does not work in source code. Sam <sam@email-scan.com> - 2011-07-28 20:41 -0500
  Re: Macro does not work in source code. red floyd <no.spam.here@its.invalid> - 2011-07-28 23:45 -0700
    Re: Macro does not work in source code. Juha Nieminen <nospam@thanks.invalid> - 2011-07-29 10:01 +0000
      Re: Macro does not work in source code. "Alf P. Steinbach" <alf.p.steinbach:usenet@gmail.com> - 2011-07-29 13:31 +0200
  Re: Macro does not work in source code. MJ_India <mail.mohitjain@gmail.com> - 2011-07-29 23:41 -0700
    Re: Macro does not work in source code. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-07-30 12:58 +0000
      Re: Macro does not work in source code. Brian Casiello <bcasiello@gmail.com> - 2011-07-30 11:39 -0400
        Re: Macro does not work in source code. Paul Brettschneider <paul.brettschneider@yahoo.fr> - 2011-07-31 18:12 +0200
          Re: Macro does not work in source code. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-07-31 18:30 +0000
            Re: Macro does not work in source code. "Alf P. Steinbach" <alf.p.steinbach:usenet@gmail.com> - 2011-08-01 00:48 +0200
              Re: Macro does not work in source code. "Alf P. Steinbach" <alf.p.steinbach:usenet@gmail.com> - 2011-08-01 00:52 +0200
                Re: Macro does not work in source code. Paul Brettschneider <paul.brettschneider@yahoo.fr> - 2011-08-01 08:58 +0200
                Re: Macro does not work in source code. "Alf P. Steinbach" <alf.p.steinbach:usenet@gmail.com> - 2011-08-01 10:11 +0200
                Re: Macro does not work in source code. James Kanze <james.kanze@gmail.com> - 2011-08-07 11:00 -0700
                Re: Macro does not work in source code. "Alf P. Steinbach" <alf.p.steinbach:usenet@gmail.com> - 2011-08-07 22:50 +0200
                Re: Macro does not work in source code. Ian Collins <ian-news@hotmail.com> - 2011-08-08 09:15 +1200
                Re: Macro does not work in source code. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-08-01 12:09 +0000
                Re: Macro does not work in source code. Miles Bader <miles@gnu.org> - 2011-08-02 14:53 +0900
              Re: Macro does not work in source code. Ian Collins <ian-news@hotmail.com> - 2011-08-01 10:55 +1200
      Re: Macro does not work in source code. James Kanze <james.kanze@gmail.com> - 2011-08-07 10:47 -0700
        Re: Macro does not work in source code. Marc <marc.glisse@gmail.com> - 2011-08-07 18:13 +0000

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