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[Help-gsl] IEEE doubles/ANSI C questions
From: |
Michael Mair |
Subject: |
[Help-gsl] IEEE doubles/ANSI C questions |
Date: |
Tue, 26 Oct 2004 12:00:39 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 |
Hi there,
I have just read through the introduction of the GSL manual and
have now two questions:
- the use of double variables is advocated over the use of long
double variables with the reasoning that doubles were IEEE
doubles and thus the same on all machines.
Even if we for a moment assume that C doubles on the considered
architectures are IEEE doubles, there is the still the
overprecision on x86 systems, so the result will of course not
be the same if -ffloat-store is not used (which OTOH would
deteriorate the performance considerably).
Is there a better rationale why one should not prefer long
double?
- The introduction talks about "ANSI C" but evidently means C89
(as it claims that there were no inline functions in ANSI C
which is wrong as of C99 which is the current ANSI C standard).
Now, I would like to know whether there are experiences or
known problems using GSL with C99 (or the gcc C99 subset
available by gcc -std=c99 -pedantic). The semantics of the
inline keyword differ in gcc -std=gnu89 and C99, but maybe the
referred-to extended autoconf checking helps finding out
whether this works or not.
It would be very kind if someone would answer these questions or
refer me to the right place to ask them.
Thanks in advance
Michael
- [Help-gsl] IEEE doubles/ANSI C questions,
Michael Mair <=