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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | VERSIONS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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copysign(3) Library Functions Manual copysign(3)
copysign, copysignf, copysignl - copy sign of a number
Math library (libm, -lm)
#include <math.h>
double copysign(double x, double y);
float copysignf(float x, float y);
long double copysignl(long double x, long double y);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
copysign(), copysignf(), copysignl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These 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.
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.
No errors occur.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────┼───────────────┼─────────┤
│ copysign(), copysignf(), │ Thread safety │ MT-Safe │
│ copysignl() │ │ │
└─────────────────────────────────────┴───────────────┴─────────┘
On architectures where the floating-point formats are not IEEE
754 compliant, these functions may treat a negative zero as
positive.
C11, POSIX.1-2008.
This function is defined in IEC 559 (and the appendix with
recommended functions in IEEE 754/IEEE 854).
C99, POSIX.1-2001, 4.3BSD.
signbit(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
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⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.9.1 2024-05-02 copysign(3)
Pages that refer to this page: signbit(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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