Guardian Native C Library Calls Reference Manual (G06.28+, H06.05+)

tan(3) Guardian Native C Library Calls Reference Manual
NAME
tan - Computes the trigonometric tangent function
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRESRL
G-series native OSS processes: /G/system/sysnn/zcresrl
H-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL
H-series OSS processes: /G/system/zdllnnn/zcredll
SYNOPSIS
#include <math.h>
double tan(
double x);
PARAMETERS
x Is the value for which the trigonometric tangent function is to be computed.
DESCRIPTION
The tan( ) function computes the tangent of x, measured in radians.
NOTES
The tan( ) function loses accuracy when passed a large value for the x parameter.
This function supports both IEEE Std 754-1985 floating-point and Tandem floating-point values
in the native environment. IEEE values can include NaN and infinity, and the sign of 0.0 (zero)
can be either positive or negative. Refer to the fp_class(3) reference page for a description of
IEEE value classes.
Guardian functions are available to convert between floating-point formats. Refer to the Guar-
dian Programmer’s Guide for a discussion of floating-point conversions.
RETURN VALUES
The tan( ) function returns the tangent of its parameter.
For IEEE floating-point values, if the value of x is NaN, NaN is returned. If the value of x is
positive or negative infinity, NaN is returned and errno is set to [EDOM].
If the correct value would cause underflow, 0.0 (zero) is returned.
ERRORS
If any of the following conditions occurs, the tan() function sets errno to the corresponding
value:
[EDOM] The value of x is infinite.
RELATED INFORMATION
Functions: acos(3), acosh(3), asin(3), asinh(3), atan(3), atan2(3), atanh(3), cos(3), cosh(3),
fp_class(3), isnan(3), sin(3), sinh(3), tanh(3).
Files: float(4), math(4).
STANDARDS CONFORMANCE
This function conforms to the XPG4 Version 2 specification with extensions when used for IEEE
floating-point data. This function conforms to the XPG4 Version 2 specification without exten-
sions when used for Tandem floating-point data.
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