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Date: Wed, 14 Oct 2009 15:23:41 +0100
From: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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To: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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Subject: Re: [warning: implicit declaration of function] if enable flag  std=c99
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Dave Korn wrote:

> If you use --std=c99, that means you want *only* c99 functions, and have 
> specifically asked to be warned about non-ANSI functions.  I don't
> understand why Linux does things differently, it's probably technically
> wrong but trying to be helpful,

  It's being POSIX compliant: the fseeko/ftello functions are denoted CX by
the opengroup SUS:

> [CX][Option Start] Extension to the ISO C standard [Option End] The
> functionality described is an extension to the ISO C standard. Application
> writers may make use of an extension as it is supported on all IEEE Std
> 1003.1-2001-conforming systems.
> 
> With each function or header from the ISO C standard, a statement to the
> effect that ``any conflict is unintentional'' is included. That is intended
> to refer to a direct conflict. IEEE Std 1003.1-2001 acts in part as a
> profile of the ISO C standard, and it may choose to further constrain
> behaviors allowed to vary by the ISO C standard. Such limitations are not
> considered conflicts.
> 
> Where additional semantics apply to a function or header, the material is
> identified by use of the CX margin legend.

  So I think it makes sense to enable these for cygwin too.  I'm whipping up a
patch for newlib.

    cheers,
      DaveK

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