sparc, ia64: Compute cos(M_PI_2l) for your 128-bit long double please.

[Carlos O'Donell]

On 04/11/2013 09:09 AM, Rich Felker wrote:
> On Thu, Apr 11, 2013 at 03:06:47PM +0200, Andreas Schwab wrote:
>> Rich Felker <dalias@aerifal.cx> writes:
>>
>>> I would just use something like "%.100000g\n".
>>
>> If you use %g you need at most DECIMAL_DIG digits.
> 
> No, that's wrong. DECIMAL_DIG is sufficient if you want to round-trip
> the value back. But here we want to print the exact value in order to
> use an external tool to apply cos() to that value.

I assume that it's sufficient to use as many digits
as M_El or M_PI_2l actually have once converted to
the type in question?

For example for float/double/long double on x86-64
M_El converts as:
2.7182817459106445312500000000000000000000000000000000000000000000000000000000000000000000000000000000e+00
2.7182818284590450907955982984276488423347473144531250000000000000000000000000000000000000000000000000e+00
2.7182818284590452354281681079939403389289509505033493041992187500000000000000000000000000000000000000e+00

Which to me indicates that %.100 was sufficient to
export this value for use in the external tool.

Cheers,
Carlos.