sscanf behaviour. bug?

[J. Johnston]

I believe I have found the problem.  It is a float-specific error - I do not
know why you have stated that it occurs for any other conversion descriptor.
For example, %d instead of %f works as expected.

I am testing a patch and will post shortly if successful.

-- Jeff J.


Hannes Krueger wrote:
> The following is from a recent thread on comp.lang.c
> and seems to be a bug in the sscanf implementation of newlib, since cygwin (with
> which this behaviour occurs) is using newlib.
> I had a look in the newlib-sources, but I wasnt able to locate this problem.
> Maybe someone else is able to?!
> 
> regards
> Hannes
> 
> the following is copied from the newsgroup:
> 
> ---
> 
> In <3e703aa8$1@sia.uibk.ac.at> student <student@dont.like.spam> writes:
> 
> 
> 
>>>I encountered some strange sscanf-behaviour.
>>>
>>>this is the line I want to parse:
>>>B0927035313520....
>>>
>>>I want to read fixed columns.
>>>
>>>sscanf(line, "%*c%2lf%2lf%2lf ...." , &val1, &val2, &val3 ....
>>>
>>>when I compile in a linux gnu environment I get
>>>val1 = 9
>>>val2 = 27
>>>val3 = 3
>>
> 
> 
> This is the correct behaviour.  %f (or any other conversion descriptor,
> for that matter) does not allow the suppression of zeros before the
> start of the conversion.
> 
> 
> 
>>>But when I compile under cygwin (gcc 3.2) on windows I get
>>>val1 = 92
>>>val2 = 70
>>>val3 = 35
>>
> 
> 
> This is broken behaviour.  You have specified a *maximum* field length
> of 2, but the first conversion used 3 characters.
> 
> 
> 
>>>It seems that the second one omits the zeros 
>>>
>>>Is this some weird gnu - non-gnu diffence? something I missed in the 
>>>documentation.
>>>Any suggestions what to do aboout that?
>>
> 
> 
> Get a non-broken implementation.  If this is not an option, use %2s
> instead and convert the strings to double with 
> (val[0] - '0') * 10.0 + val[1] - '0'.
> 
> If needed, you can also check the validity of the strings with 
> isdigit((unsigned char)val[0]) && isdigit((unsigned char)val[1])
> 
> Dan
> --
> Dan Pop
> DESY Zeuthen, RZ group
> Email: Dan.Pop@ifh.de
> 
> 
>