x SuSE Linux 13.1-RELEASE x x SuSE Linux 13.1-RELEASEx 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 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 appen- dix with recommended functions in IEEE 754/IEEE 854). NOTES On architectures where the floating-point formats are not IEEE 754 com- pliant, these functions may treat a negative zero as positive. SEE ALSO signbit(3) COLOPHON This page is part of release 3.69 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 http://www.kernel.org/doc/man-pages/. GNU 2013-10-14 COPYSIGN(3)
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