---
name: "sincos"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/sincos"
---

# sincos(3)

calculate sin and cos simultaneously

## 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)](/sin/3.md) and [**cos**(3)](/cos/3.md).

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)](/math_error/7.md) 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)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **sincos**(), **sincosf**(), **sincosl**() | Thread safety | MT-Safe |

## STANDARDS

GNU.

## HISTORY

glibc 2.1.

## NOTES

To see the performance advantage of **sincos**(), it may be necessary to disable [**gcc**(1)](/gcc/1.md) 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)](/cos/3.md), [**sin**(3)](/sin/3.md), [**tan**(3)](/tan/3.md)