NAME

sincos, sincosf, sincosl - calculate sin and cos simultaneously

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);

Link with -lm.

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: x is an infinity

errno is set to EDOM (but see BUGS). An invalid floating-point exception (FE_INVALID) is raised.

VERSIONS

These functions first appeared in glibc in version 2.1.

ATTRIBUTES

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

CONFORMING TO

These functions are GNU extensions.

NOTES

To see the performance advantage of sincos(), it may be necessary to disable gcc(1) built-in optimizations, using flags such as:

cc -O -lm -fno-builtin prog.c

BUGS

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

SEE ALSO

cos(3), sin(3), tan(3)

COLOPHON

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