[wayne@cs.toronto.edu: Cygwin-1.5.5 sscanf on floats: 20 times slower than 2 years ago]

J. Johnston jjohnstn@redhat.com
Fri Nov 21 19:53:00 GMT 2003


Wayne Hayes wrote:
>>Since scanf and the floating point arithmetic is implemented in newlib,
>>I've redirected this message there.  Does anybody have an idea, what
>>could slow down float scanning in sscanf by a factor of 20?
> 
> 
> Thanks!  Just to be pedentic, I realized that it's worse than a factor of 20.
> My *entire simulation* slows down by a factor of 20; there's significant
> other computation in it.  So the scanf slowdown is probably closer to
> hundreds of times.  *Something* fishy must be going on.  :-)
> 

The reason for the slow down is long double support.  A new routine _strtold is 
used instead of _strtod_r.  I am working on a patch to use the old routine for 
non-long-doubles to avoid the slow down.

-- Jeff J.


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