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Section: Linux Programmer's Manual (3)
Updated: 2008-08-05
Index Return to Main Contents

NAME

tan, tanf, tanl - tangent function

SYNOPSIS

#include <math.h>

double tan(double x);


float tanf(float x);


long double tanl(long double x);

Link with -lm.

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

tanf(), tanl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

The tan() function returns 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: An invalid floating-point exception (FE_INVALID) is raised.
Range error: result overflow: An overflow floating-point exception (FE_OVERFLOW) is raised.

These functions do not set errno.

CONFORMING TO

C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.

COLOPHON

This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

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