Updated: 2021/Apr/14


ISINF(3)                   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.

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").

CAVEATS
     On VAX the isinf() function always returns 0, as the architecture doesn't
     have a representation for infinity.

NetBSD 9.99                   September 27, 2017                   NetBSD 9.99