standards/56906: Several math(3) functions fail to set errno on a domain error

[Stefan Farfeleder]

The following reply was made to PR standards/56906; it has been noted by GNATS.

From: Stefan Farfeleder <stefan at fafoe.narf.at>
To: Bruce Evans <bde at zeta.org.au>
Cc: bug-followup at freebsd.org, freebsd-standards at freebsd.org
Subject: Re: standards/56906: Several math(3) functions fail to set errno on a domain error
Date: Tue, 16 Sep 2003 15:08:07 +0200

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 On Tue, Sep 16, 2003 at 11:42:44AM +1000, Bruce Evans wrote:
 > On Tue, 16 Sep 2003, Stefan Farfeleder wrote:
 > 
 > > >Synopsis:       Several math(3) functions fail to set errno on a domain error
 > 
 > This is intentional.
 > 
 > > >Description:
 > > ISO C90 says that errno must be set to EDOM if a domain error occurs.
 > 
 > As you probably know, C99 doesn't require this.  FreeBSD, or at least I,
 > decided not to support C90's relatively feeble and broken specification
 > of floating point and wait for C99 to get it right.  The wait is long
 > over and the nonstandardness is now a little different.
 
 Hm, having a conforming C90 environment would be nice despite C99's
 existence as older compliant applications may depend on the former
 behaviour and don't become magically C99 conformant.  Is there a chance
 to have a separated C90 compliant libm?
 
 Anyway, here's a patch to give C99 application at least the possibility
 to notice that errno doesn't get set for these functions.  Because we
 don't have <fenv.h> to access the floating point status flags, I'm
 setting math_errhandling to 0.
 
 Stefan
 
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 Index: src/lib/msun/src/math.h
 ===================================================================
 RCS file: /usr/home/ncvs/src/lib/msun/src/math.h,v
 retrieving revision 1.26
 diff -u -r1.26 math.h
 --- src/lib/msun/src/math.h	22 May 2003 17:07:57 -0000	1.26
 +++ src/lib/msun/src/math.h	16 Sep 2003 12:31:42 -0000
 @@ -339,4 +339,10 @@
  #endif /* !_ANSI_SOURCE && !_POSIX_SOURCE */
  __END_DECLS
  
 +#if __ISO_C_VISIBLE >= 1999
 +#define	MATH_ERRNO	1
 +#define	MATH_ERREXCEPT	2
 +#define	math_errhandling	0
 +#endif
 +
  #endif /* !_MATH_H_ */
 
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