sincos(3)

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

VERSIONS
These functions were added in glibc 2.1.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value
 | Thread safety | MT-Safe

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

SEE ALSO
cos(3), sin(3), tan(3)