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Re: C Macro define contain symbol #

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On Fri, 16 Sep 2011 00:34:20 +0300, Phil Carmody wrote:

>> >     ... if you really think you need "pack(1)".  Usually (not always,
>> >but usually) that's the sign of a short-term hack leading to long-
>> >term headaches.
>> 
>> Not when you are dealing with communication protocols, mapping
>> hardware control registers in embedded systems, etc.
> 
> Packing doesn't address endianness. You have lost already.

It doesn't matter for the "hardware control registers" case, as these are
inherently in the native byte order.

It doesn't always matter for the case of communication protocols; some
protocols offer a choice of byte order. Similarly for file formats.

For floating-point values, reading bytes directly into a C float/double
then optionally byte-swapping is rather common. If your platform doesn't
use IEEE-754 representation, you lose.

Even if portability is important enough to justify explicit
(de)serialisation code, performance is often important enough to justify:

	#if FILE_FORMAT_IS_NATIVE_FORMAT
		return fwrite(&obj, sizeof(obj), 1, fp);
	#else
		// explicit seralisation
	#endif

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C Macro define contain symbol # Wang WolfLouis <wolflouiswang@gmail.com> - 2011-09-13 02:47 -0700
  Re: C Macro define contain symbol # Noob <root@127.0.0.1> - 2011-09-13 13:14 +0200
  Re: C Macro define contain symbol # Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-13 07:55 -0400
    Re: C Macro define contain symbol # Roberto Waltman <usenet@rwaltman.com> - 2011-09-13 08:24 -0400
      Re: C Macro define contain symbol # Keith Thompson <kst-u@mib.org> - 2011-09-13 11:12 -0700
        Re: C Macro define contain symbol # Keith Thompson <kst-u@mib.org> - 2011-09-13 20:19 -0700
          Re: C Macro define contain symbol # Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-16 00:43 +0300
            Re: C Macro define contain symbol # Keith Thompson <kst-u@mib.org> - 2011-09-15 18:34 -0700
        Re: C Macro define contain symbol # Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-13 22:51 -0400
          Re: C Macro define contain symbol # Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-14 12:16 +0100
      Re: C Macro define contain symbol # tom st denis <tom@iahu.ca> - 2011-09-13 11:20 -0700
      Re: C Macro define contain symbol # Ian Collins <ian-news@hotmail.com> - 2011-09-14 07:55 +1200
      Re: C Macro define contain symbol # Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-14 07:58 -0400
        Re: C Macro define contain symbol # Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-09-14 14:54 +0000
      Re: C Macro define contain symbol # Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-16 00:34 +0300
        Re: C Macro define contain symbol # Nobody <nobody@nowhere.com> - 2011-09-16 12:07 +0100
    Re: C Macro define contain symbol # "BartC" <bc@freeuk.com> - 2011-09-13 13:50 +0100
      Re: C Macro define contain symbol # James Kuyper <jameskuyper@verizon.net> - 2011-09-13 08:59 -0400
        Re: C Macro define contain symbol # Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-09-14 15:02 +0000
  Re: C Macro define contain symbol # Kenneth Brody <kenbrody@spamcop.net> - 2011-09-13 16:54 -0400

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