class(3M)

NAME
     fpclassify, isfinite, isinf, isnormal, isunordered, signbit -
     classification macros

SYNOPSIS
     #include <math.h>

     int fpclassify(real-floating x);
     int isfinite(real-floating x);
     int isinf(real-floating x);
     int isnormal(real-floating x);
     int isunordered(real-floating x);
     int signbit(real-floating x);

DESCRIPTION
     These routines are not available for programs compiled with the O32
     ABI.

     These macros return the appropriate function for their argument type.

     Functions in the standard math library (libm.a) are referred to as -lm
     versions. Those in the libmx library (libmx.a) are referred to as -lmx
     versions, and those in the the BSD math library (libm43.a) are
     referred to as -lm43 versions.  These functions are not available for
     libm43 or libmx.

     real-floating indicates that the argument is an expression of real
     floating type.

     The fpclassify macro returns the value of the number classification
     macro appropriate to the value of its argument.

     The isinfinite macro returns a non-zero value if and only if its
     argument has a finite value.

     The isinf macro returns a nonzero value if its argument has an
     infinite value.

     The isnormal macro returns a nonzero value if its argument has a
     normal value.

     The signbit macro determines if the sign of its argument value is
     negative.

     The isunordered macro returns 1 if its arguments are unordered and
     returns 0 otherwise.

RETURN VALUES
     The -lm and -lmx versions always return the default Quiet NaN and set
     errno to EDOM when a NaN is used as an argument.

SEE ALSO
     math(3M), isnan(3C)