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a = std::numeric_limits<float>::quiet_NaN();
b = std::numeric_limits<float>::signaling_NaN();local a = 0/0Lua does not differentiate between quiet or signalling NaN's.
# built-in support (use POSIX not needed))
my $a = 'nan';
say $a;
# prints string value: nan
say 0 + $a;
# prints numeric value: NaN
Part 1: built-in support. You can assign 'nan' to a scalar variable and perl will create a dualvar that has 'nan' as it's string value and NaN as it's numeric value. Adding 0 to $a forces numeric context, yielding NaN.
say isnan($a) ? 'true' : 'false';;
# prints true
say $a == $a ? 'true' : 'false';
# prints false because NaN does not equal NaN
say issignaling($a) ? 'true' : 'false';
# prints false because $a is non-signaling
my $b = nan(999); # set to signaling NaN by adding a payload
say $b;
# prints NaN
say getpayload($b);
# prints 999
Part 2: Not built-in, but the core POSIX module is included in the perl installation and provides a lot of other functionality for NaN as well as Inf.
a = float('nan')
Python makes no effort to distinguish signaling NaNs from quiet NaNs, and behavior for signaling NaNs remains unspecified. Typical behavior is to treat all NaNs as though they were quiet.
a = Float::NANRuby does not differentiate between quiet or signalling NaN's.
let a: f64 = f64::NAN;