Bug#47784: Log doesn't honour NaN on log(-8)

[Bart Warmerdam <bartw@xs4all.nl>]

Package: libc6.1
Version: 2.1.2-5

The log() function doesn't give the right answer on negative log values. E.g.
log(-8), as used in the testcase of mawk, returns 0.00000 while it should be
NaN.
Example attached.

Thanks,

B.
  

--
B. Warmerdam                                              GNU/Debian Linux
bartw@xs4all.nl, bartw@debian.org (Keyid: 10A0FDD1)       ----------------

#include <stdio.h>
#include <math.h>

int main()
{
	printf("%f\n", log(-8));
	exit(0);
}