> Michael Chirico
> on Sat, 12 Jan 2019 17:34:03 +0800 writes:
> Thanks Martin. For what it's worth, this extremely
> representative, highly scientific Twitter poll suggests
> the Mac/Linux split is pretty stark (NA on Mac, 0 on
> Linux)
> https://twitter.com/michael_chirico/status/1083649190117306369?s=17
> On Sat, Jan 12, 2019, 2:00 AM Martin Maechler
> > > Martin Maechler > on Fri, 11 Jan 2019 09:44:14
>> +0100 writes:
>>
>> > Michael Chirico > on Fri, 11 Jan 2019 14:36:17
>> +0800 writes:
>>
>> >> Identified as root cause of a bug in data.table: >>
>> https://github.com/Rdatatable/data.table/issues/3267
>>
>> >> On my machine, strtoi("", base = 2L) produces
>> NA_integer_ >> (which seems consistent with ?strtoi:
>> "Values which >> cannot be interpreted as integers or
>> would overflow are >> returned as NA_integer_").
>>
>> > indeed consistent with R's documentation on strtoi().
>> > What machine would that be?
>>
>> >> But on all the other machines I've seen, 0L is >>
>> returned. This seems to be consistent with the output of
>> >> a simple C program using the underlying strtol
>> function >> (see data.table link for this program, and
>> for full >> sessionInfo() of some environments with
>> differing >> output).
>>
>> >> So, what is the correct output of strtoi("", base =
>> 2L)?
>>
>> >> Is the cross-platform inconsistency to be >>
>> expected/documentable?
>>
>> > The inconsistency is certainly undesirable. The
>> relevant > utility function in R's source
>> (/src/main/character.c) > is
>>
>> > static int strtoi(SEXP s, int base) { long int res;
>> char > *endp;
>>
>> > /* strtol might return extreme values on error */ >
>> errno = 0;
>>
>> > if(s == NA_STRING) return(NA_INTEGER); res = >
>> strtol(CHAR(s), &endp, base); /* ASCII */ if(errno || >
>> *endp != '\0') res = NA_INTEGER; if(res > INT_MAX || res
>> < > INT_MIN) res = NA_INTEGER; return (int) res; }
>>
>> > and so it clearly is a platform-inconsistency in the >
>> underlying C library's strtol().
>>
>> (corrected typos here: )
>>
>> > I think we should make this cross-platform consistent
>> ... > and indeed it makes much sense to ensure the
>> result of
>>
>> > strtoi("", base=2L) to become NA_integer_
>>
>> > but chances are that would break code that has relied
>> on > the current behavior {on "all but your computer"
>> ;-)} ?
>>
>> I still think that such a change should be done.
>>
>> 'make check all' on the R source (+ Recommended packages)
>> seems not to signal any error or warning with such a
>> change, so I plan to commit that change to "the trunk" /
>> "R-devel" soon, unless concerns are raised highly (and
>> quickly enough).
I've now committed svn rev 75977 to R-devel which does change
strtoi("", ) to return NA_integer_ (for all )
platform independently, not even calling lib C's strtol() in
that case.
Martin
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