HP-UX Reference (11i v1 00/12) - 3 Library Functions N-Z (vol 7)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/nan.3m
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signbit(3M) signbit(3M)
NAME
signbit() - floating-point sign-determination macro
SYNOPSIS
#include <math.h>
int signbit(
floating-type x);
DESCRIPTION
The signbit() macro determines whether the sign of its argument value is negative. The macro can be
used with either double or float arguments, including infinities, zeros, and NaNs.
The ISO/ANSI C committee has approved the signbit() macro for inclusion in the C9X draft standard.
To use the signbit() macro, compile either with the default -Ae option or with the -Aa and
-D_HPUX_SOURCE options. Make sure your program includes <math.h>. Link in the math library by
specifying -lm on the compiler or linker command line.
RETURN VALUE
The signbit() macro returns a nonzero value if and only if the sign of its argument value is negative.
ERRORS
No errors are defined.
EXAMPLE
Take certain actions if x is negative zero:
#include <math.h>
/*...*/
double x;
/*...*/
if ( (x == 0.0) && signbit(x) ) {
/*...*/
}
SEE ALSO
finite(3M), fpclassify(3M), isfinite(3M), isinf(3M),isnan(3M), isnormal(3M), math(5).
HP-UX Release 11i: December 2000 − 1 − Section 3−−857
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