HP-UX Floating-Point Guide

Appendix A 197
The C Math Library
C Math Library Tables
Other Transcendental Functions (cont.)
double atanh(double x); Returns inverse hyperbolic tangent of x.
double cosh(double x); Returns hyperbolic cosine of x.
double erf(double x); Returns error function of x.
double erfc(double x); Returns 1.0 − erf(x).
double exp(double x); Returns exponential function of x.
(Millicode version available)
double exp2(double x);
Returns 2.0
x
.
double expm1(double x); Returns exp(x) − 1.
double gamma(double x); Returns logarithm of the absolute value of
the gamma function of x (same as
lgamma). (Obsolescent; will become true
gamma function at a future release)
int ilogb(double x); Returns the integer form of the binary
exponent of the floating-point value x.
double j0(double x); Returns Bessel function of x of the first
kind of order 0.
double j1(double x); Returns Bessel function of x of the first
kind of order 1.
double jn(int n, double x); Returns Bessel function of x of the first
kind of order n.
double lgamma(double x); Returns logarithm of the absolute value of
the gamma function of x.
double lgamma_r(double x,
int *sign);
Returns logarithm of the absolute value of
the gamma function of x (reentrant
version of lgamma).
double log(double x); Returns natural logarithm of x. (Millicode
version available)
Function What It Does