NAME
copysign, copysignf, copysignl - copy sign of a number SYNOPSIS
#include
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 featuretestmacros(7)): copysign(), copysignf(), copysignl(): SVIDSOURCE || BSDSOURCE || XOPENSOURCE >= 600 || ISOC99SOURCE || POSIXCSOURCE >= 200112L;
or cc -std=c99 DESCRIPTION The copysign() 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. This function is defined in IEC 559 (and the appen‐ dix with recommended functions in IEEE 754/IEEE 854). NOTES
On architectures where the floating-point formats are not IEEE 754 com‐ pliant, the copysign() functions may treat a negative zero as positive. SEE ALSO signbit(3) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-03-25 COPYSIGN(3)