isnan(3M)isnan(3M)NAMEisnan() - floating-point test for NaN
The macro determines whether its argument is a NaN. The argument must
be of floating type. For HP Integrity servers, the argument can be any
floating type. For PA-RISC, the argument must be either or
The macro implements the functionality recommended by the IEEE-754
standard for floating-point arithmetic.
The macro replaces the and functions, which are obsolete and are no
To use the macro, compile either with the default option or with the
and options. Make sure your program includes Link in the math library
by specifying on the compiler or linker command line.
The macro returns a nonzero value if and only if its argument has a NaN
value. The macro raises no floating-point exceptions.
No errors are defined.
Take certain actions if is not a NaN:
SEE ALSOfpclassify(3M), isfinite(3M), isinf(3M), isnormal(3M), signbit(3M),