isinf(3) - NetBSD Manual Pages

ISINF(3)                NetBSD 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 (posi-
     tive 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 infin-
     ity.  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'').

NetBSD 7.0                       March 5, 2004                      NetBSD 7.0