COPYSIGN
Section: Linux Programmer's Manual (3)
Updated: 2013-10-14
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NAME
copysign, copysignf, copysignl - copy sign of a number
SYNOPSIS
#include <math.h>
double copysign(double x, double y);
float copysignf(float x, float y);
long double copysignl(long double x, long double y);
Link with -lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
copysign(),
copysignf(),
copysignl():
-
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
DESCRIPTION
The
copysign(),
copysignf(),
and
copysignl()
functions return a value whose absolute value matches
that of
x,
but whose sign bit matches that of
y.
For example,
copysign(42.0, -1.0)
and
copysign(-42.0, -1.0)
both return -42.0.
RETURN VALUE
On success, these functions return a value whose magnitude is taken from
x
and whose sign is taken from
y.
If
x
is a NaN,
a NaN with the sign bit of
y
is returned.
ERRORS
No errors occur.
ATTRIBUTES
Multithreading (see pthreads(7))
The
copysign(),
copysignf(),
and
copysignl()
functions are thread-safe.
CONFORMING TO
C99, POSIX.1-2001.
This function is defined in IEC 559 (and the appendix with
recommended functions in IEEE 754/IEEE 854).
NOTES
On architectures where the floating-point formats are not IEEE 754 compliant,
these
functions may treat a negative zero as positive.
SEE ALSO
signbit(3)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- Multithreading (see pthreads(7))
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
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Time: 02:55:17 GMT, September 18, 2014