COPYSIGN, COPYSIGNF, COPYSIGNL - reference manual online

Copy sign of a number.

COPYSIGN(3)                         Linux Programmer's Manual                         COPYSIGN(3)

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 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.
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 For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├─────────────────────────────────────┼───────────────┼─────────┤ │copysign(), copysignf(), copysignl() │ Thread safety │ MT-Safe │ └─────────────────────────────────────┴───────────────┴─────────┘
CONFORMING TO C99, POSIX.1-2001, POSIX.1-2008. 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 func‐ tions may treat a negative zero as positive.
SEE ALSO signbit(3)
COLOPHON This page is part of release 4.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at
GNU 2015-04-19 COPYSIGN(3)
This manual Reference Other manuals
copysign(3) referred by signbit(3)
refer to attributes(7) | feature_test_macros(7) | signbit(3)