On Thu, Nov 21, 2013 at 10:23 AM, Cedric Blancher <[email protected] > wrote:
> On 21 November 2013 15:36, Glenn Fowler <[email protected]> wrote: > > On Thu, Nov 21, 2013 at 9:05 AM, Cedric Blancher < > [email protected]> > > wrote: > >> > >> On 21 November 2013 14:34, Glenn Fowler <[email protected]> > wrote: > >> > nice find > >> > proposed descriptions for getpayload[fl]() setpayload[fl]() > >> > >> What are the exact prototypes for a float, double and long double > >> arguments? > >> > >> > setpayloadsig[fl]() are in > >> > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1664.pdf > >> > as a bonus these functions provide a way to create a nan without > >> > resorting > >> > to strtod("nan",0) > >> > i.e., exactly what ast need because it provides strtod() sfscanf() > etc. > >> > this is what i was anticipating in the ast nan payload patch > >> > > >> > the only disconnect is that the api deals with floating payloads but > >> > describes the payloads themselves as non-negative integers > >> > I guess they do this in case the largest payload value is greater than > >> > the > >> > largest native integer > >> > >> nans can only be positive integers >= 1 > > > > > > the proposed api probably needs some tightening > > its does not mention what is returned for a nan that has no payload > > specified > > Its undefined and implementation specific? :) > getpayload() would need an error indication or the whole api would be useless (no way to determine nan that has no payload) presumably they expect the caller to have somehow verified isnan(x) before calling getpayload(&x) it would then be reasonable to return 0 for nans with no payload > > like you note it only allows positive integer payloads which excludes 0 > > Well, that's the mathematics viewpoint. The C datatypes are always > positive or negative.
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