isinf(3) [netbsd man page]

ISINF(3)						   BSD Library Functions Manual 						  ISINF(3)

NAME

     isinf -- test for infinity

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <math.h>

     int
     isinf(real-floating x);

DESCRIPTION

     The isinf() macro determines whether its argument x is an infinity (positive or negative).  An argument represented in a format wider than
     its semantic type is converted to its semantic type first.  The determination is then based on the type of the argument.

   IEEE 754
     It is determined whether the value of x is an infinity.

   VAX
     Infinities are not supported.

RETURN VALUES

     The isinf() macro returns a non-zero value if the value of x is an infinity.  Otherwise 0 is returned.

SEE ALSO

     fpclassify(3), isfinite(3), isinff(3), isnan(3), isnanf(3), isnormal(3), math(3), signbit(3)

     IEEE Standard for Binary Floating-Point Arithmetic, Std 754-1985, ANSI.

STANDARDS

     The isinf() macro conforms to ISO/IEC 9899:1999 (``ISO C99'').

BSD
								   March 5, 2004							       BSD

FPCLASSIFY(3)						   BSD Library Functions Manual 					     FPCLASSIFY(3)

NAME

     fpclassify, isfinite, isinf, isnan, isnormal -- classify a floating-point number

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     int
     fpclassify(real-floating x);

     int
     isfinite(real-floating x);

     int
     isinf(real-floating x);

     int
     isnan(real-floating x);

     int
     isnormal(real-floating x);

DESCRIPTION

     The fpclassify() macro takes an argument of x and returns one of the following manifest constants.

     FP_INFINITE   Indicates that x is an infinite number.

     FP_NAN	   Indicates that x is not a number (NaN).

     FP_NORMAL	   Indicates that x is a normalized number.

     FP_SUBNORMAL  Indicates that x is a denormalized number.

     FP_ZERO	   Indicates that x is zero (0 or -0).

     The isfinite() macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value.  The isinf(),
     isnan(), and isnormal() macros return non-zero if and only if x is an infinity, NaN, or a non-zero normalized number, respectively.

     The symbol isnanf() is provided as an alias to isnan() for compatibility, and its use is deprecated.  Similarly, finite() and finitef() are
     deprecated versions of isfinite().

SEE ALSO

     isgreater(3), math(3), signbit(3)

STANDARDS

     The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY

     The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros were added in FreeBSD 5.1.  3BSD introduced isinf() and isnan() func-
     tions, which accepted double arguments; these have been superseded by the macros described above.

BSD
								 January 26, 2005							       BSD