FPCLASSIFY(3) Library Functions Manual FPCLASSIFY(3)
NAME
fpclassifyclassify real floating type
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <math.h>
int
fpclassify(real-floating x);
DESCRIPTION
The fpclassify() macro performs classification of its argument x. An argument represented in a format wider than its semantic type is converted to its semantic type first. The classification is then based on the type of the argument.
IEEE 754
FP_INFINITE
infinity, either positive or negative
FP_NAN
not-a-number (“NaN”)
FP_NORMAL
normal
FP_SUBNORMAL
subnormal
FP_ZERO
zero
VAX
FP_ROP
reserved operand (“ROP”)
FP_DIRTYZERO
dirty zero
FP_NORMAL
finite
FP_ZERO
true zero
RETURN VALUES
The fpclassify() macro returns the value of the number classification macro appropriate to its argument x as described above.
ERRORS
No errors are defined.
SEE ALSO
STANDARDS
The fpclassify() macro conforms to ISO/IEC 9899:1999 (“ISO C99”).