HP-UX Floating-Point Guide

Chapter 4 119

HP-UX Math Libraries on HP 9000 Systems

Contents of the HP-UX Math Libraries

rint(x) Rounds x to integer-valued

double-precision number, in the

direction of the current rounding

mode

scalb(x, y) Returns x*(2**y)

To use these functions, compile your program in any mode except strict

ANSI mode (-Aa). Use either extended ANSI mode (-Ae, the default),

non-ANSI mode (-Ac), or -Aa -D_HPUX_SOURCE.

The fenv(5) Suite

The fenv(5) suite is a collection of functions in the C math library that

allow an application to manipulate various modiﬁable control modes and

status ﬂags in the ﬂoating-point status register. The ISO/ANSI C

committee has included most of the functions in the fenv(5) suite in the

C9X draft standard.

For details on how to use these functions, see Chapter 5 and the online

man pages. The tables in Appendix A also list all of the functions.

C9X Functions and Macros

The C math library at Release 11.0 supports a number of additional

functions and macros that the ISO/ANSI C committee has included in

the C9X draft standard. These are:

exp2(x) Returns 2**x

fdim(x, y) Returns the positive difference

between x and y

fmax(x, y) Returns the maximum numeric value

of x and y

fmin(x, y) Returns the minimum numeric value

of x and y

isgreater(x, y) (Macro) Returns the value of (x)>(y)

isgreaterequal(x, y) (Macro) Returns the value of

(x)>=(y)

isless(x, y) (Macro) Returns the value of (x) < (y)

islessequal(x, y) (Macro) Returns the value of

(x)<=(y)