tanf(3)

tanf3

Tangent function

Part of tan(3).

Usage

#include <math.h>

double tan(double x); float tanf(float x); long double tanl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

tanf(), tanl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

Library

Math library (libm, -lm)

Overview

These functions return the tangent of x, where x is given in radians.

Return value

On success, these functions return the tangent of x.

If x is a NaN, a NaN is returned.

If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.

If the correct result would overflow, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with the mathematically correct sign.

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.

Range error: result overflow

An overflow floating-point exception (FE_OVERFLOW) is raised.

Attributes

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

InterfaceAttributeValue
tan(), tanf(), tanl()Thread safetyMT-Safe

Releases

12 releases since Debian 3.1 (Sarge); the text changed 11 times.

  1. 3.1
  2. 4.0
  3. 5.0
  4. 6.0
  5. 7
  6. 8
  7. 9
  8. 10
  9. 11
  10. 12
  11. 13
  12. Arch

Standards

C11, POSIX.1-2008.

History

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

Bugs

Before glibc 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.