Re: gawk infinity issues

[Andrew J. Schorr]

On Thu, Jan 05, 2006 at 06:18:31PM -0500, Andrew J. Schorr wrote:
> Understood.  But it still seems to me that gawk should have a clear policy
> (even if not defined by POSIX) on how it will convert to a number a string
> that contains a (platform-dependent) representation of Infinity or NaN.  
> Or do you feel that this behavior need not be nailed down?

In other words, this seems strange to me:

On Solaris 8/sparc:
   $ ./gawk -v x=inf 'BEGIN {print x+0}'
   0
   $ ./gawk -v x=-inf 'BEGIN {print x+0}'
   -Inf
   $ ./gawk -v x=nan 'BEGIN {print x+0}'
   0
   $ ./gawk -v x=-nan 'BEGIN {print x+0}'
   -NaN

On linux/x86/32-bits:
   $ ./gawk -v x=inf 'BEGIN {print x+0}'
   0
   $ ./gawk -v x=-inf 'BEGIN {print x+0}'
   0
   $ ./gawk -v x=nan 'BEGIN {print x+0}'
   0
   $ ./gawk -v x=-nan 'BEGIN {print x+0}'
   0

On both platforms, the libc strtod() function recognizes the
strings "inf", "-inf", "nan", and "-nan", but the gawk code
seems to vary on whether it interprets the string using strtod.

Note that config.h defines STRTOD_NOT_C89 on linux (and uses gawk_strtod
instead), and not on solaris, and this seems to be a factor.  It
doesn't look like gawk_strtod has any support for nan or inf.

Regards,
Andy