Re: printf-safe checks of invalid long double values

[Paul Eggert]

Pádraig Brady wrote:
>    Are these checks backed up by corresponding replacement code?
>    Are these checks correct?
>    Why has glibc not been updated in the 7 years since the checks were added?

As I recall, this comes from an old dispute about what glibc should do when 
asked to print floating-point bit-patterns that cannot be generated by the 
machine's floating-point operations.  This has undefined behavior in glibc (and 
POSIX allows this), but undefined behavior can be catastrophic in programs like 
'od' which will crash when asked to print arbitrary data as if it were 
floating-point.  So coreutils insists on a substitute for printf for this situation.

See the thread starting here:

http://lists.gnu.org/archive/html/bug-gnulib/2007-06/msg00046.html