sincos(3)

NAME#

sincos, sincosf, sincosl - calculate sin and cos simultaneously

LIBRARY#

Math library (libm, -lm)

SYNOPSIS#

#define _GNU_SOURCE\n         /* See feature_test_macros(7) */
\n#include <math.h>

void sincos(double \nx\n, double *\nsin\n, double *\ncos\n);\n
\nvoid sincosf(float \nx\n, float *\nsin\n, float *\ncos\n);\n
\nvoid sincosl(long double \nx\n, long double *\nsin\n, long double *\ncos\n);

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.

ATTRIBUTES#

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

STANDARDS#

GNU.

HISTORY#

glibc 2.1.

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)