Re: Crashing g_string_sprintf when printing invalid floats. gtk+-1.2.9 on Linux

Allin Cottrell wrote:

Isn't that undefined behavior, trying to access the wrong member of a

Yes.  I am using that to force a bad floating point value.

Here (gtk 2.0.6) it prints "0.00", but I don't see that it's
obliged to.

I feel it should not crash on any input.

I have a similar test case, which uses:

tmp_float = (float)strtod("6.0e-44",NULL);

and produces the same crash. In that case, a "%g\n" format string returns something within precision distance of 6.0e-44. The compiler (gcc 2.95) accepts that a float can be denormalized, and operates on it in various ways, but the g_string_sprintf() function does not.

The above is completely legal way to produce the crash, and an application could well convert a (very small) double to a float and then later try to print the float in a limited precision output format. That argues that the correct behavior is indeed "0.00", and nothing else.

I guess the alternative would be to print "nan", but I'd vote for "0.00" instead.


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