XPath: Empty string should be NaN, not zero

[koalo]

In my understanding of '4.4 Number functions' of XML Path Language (XPath) Version 1.0:

a string that consists of optional whitespace followed by an optional minus sign followed
by a Number followed by whitespace is converted to the IEEE 754 number that is nearest
(according to the IEEE 754 round-to-nearest rule) to the mathematical value represented
by the string; any other string is converted to NaN

I would expect that an empty string is converted to NaN.

Currently, libyang converts it into 0 (see

libyang/src/xpath.c

Line 692 in 4c73341

num = strtold(str, &ptr);

which uses strtold that returns 0 without error for an empty string).

Do you agree or do I read the standard wrong again (as in #2140 that is remotely related)?

[michalvasko]

Yep, I think you are right and it should be fixed.

[koalo]

That was quick! Works as expected now, thanks!