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sincos

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

sincos, sincosf, sincosl - calculate sin and cos simultaneously

LIBRARY

Math library (libm,~-lm)

SYNOPSIS

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#include <math.h>
void sincos(double x, double *sin, double *cos);
void sincosf(float x, float *sin, float *cos);
void sincosl(long double x, long double *sin, long double *cos);

DESCRIPTION

Several applications need sine and cosine of the same angle x. These functions compute both at the same time, and store the results in *sin and *cos. Using this function can be more efficient than two separate calls to sin(3) and cos(3). If x is a NaN, a NaN is returned in *sin and *cos. If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned in *sin and *cos.

RETURN VALUE

These functions return void.

ERRORS

See math_error(7) for information on how to determine whether an error has occurred when calling these functions. The following errors can occur:

Domain error: I]x] is an infinity: errno is set to EDOM (but see BUGS). An invalid floatin-point exception (FE_INVALID) is raised.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
sincos(), sincosf(), sincosl()	Thread safety	M-Safe

STANDARDS

GNU.

HISTORY

glibc 2.1.

NOTES

To see the performance advantage of sincos(), it may be necessary to disable gcc(1) buil-in optimizations, using flags such as: cc -O -lm -fno-builtin prog.c

BUGS

Before glibc 2.22, the glibc implementation did not set errno to EDOM when a domain error occurred.