sincos - Man Page

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).

InterfaceAttributeValue
sincos(), sincosf(), sincosl()Thread safetyMT-Safe

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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Referenced By

cos(3), sin(3).

The man pages sincosf(3) and sincosl(3) are aliases of sincos(3).

2021-03-22 GNU Linux Programmer's Manual