Re: (elisp)Numbers

[Andreas Schwab]

Richard Stallman <address@hidden> writes:

>     2.  In (elisp)Math Functions, it is said that asin, acos, log, log10
>       and sqrt all return NaN values for out-of-range arguments, but, on
>       my machine, only `sqrt' does.  The others throw an error, see the
>       IELM run below.
>
> I get the same results.  I figured out why.  I'm using an x86.  Facos
> calls acos, but in Fsqrt the call to sqrt gets open-coded using the
> fsqrt instruction.  fsqrt doesn't set errno as it is expected to.
> Perhaps that is a GCC bug.

GCC does not fully support C99 yet.

According to C99 a domain error results in an implementation-defined
value, and if math_errhandling & MATH_ERRNO is non-zero, errno is set
appropriately.

Andreas.

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Andreas Schwab, SuSE Labs, address@hidden
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