[Gpsbabel-code] sscanf blindness on optional fields

[Robert L. <rob...@us...>]

I'm losing my mind and thought I'd offer someone here a chance to make
fun of me.

Throughout the code, we make use of the ability of scanf to match
the inversion of a given set of characters.   I'm staring at a problem
report that boils down to the following case:

#include <stdio.h>
main()
{
        int d;
        char one[20]="one", two[20]="two";

        d = sscanf(",blah", "%[^,]%c", one, two);
        printf("Scanned %d\n", d);
        printf("One: '%s'\n", one);
        printf("Two: '%s'\n", two);
}

It's my expectation that 'one' should match on characters up to the
comma (which would happen to be none and therefore be a null terminated
buffer) and 'two' would get the next character which would happen to
be the comma. On multiple OSes, sscanf is returning zero indicating
matching failures so that match is just not happening. Neither buffer is
stored into, of course.

We use this construct in several places through the code, so either we
have this broken in several places or I'm overlooking something dumb.

What am I missing?

RJL