trunc(3M)

NAME

trunc(), truncf(), truncl(), truncw(), truncq() — truncation functions

SYNOPSIS

#include <math.h>

double trunc(double x);

HP Integrity Server Only

float truncf(float x);

long double truncl(long double x);

extended truncw(extended x);

quad truncq(quad x);

DESCRIPTION

The trunc() function rounds its argument to the integral value, in floating-point format, nearest to but no larger in magnitude than the argument.

Integrity Server Only

truncf() is a float version of trunc(); it takes a float argument and returns a float result.

truncl() is a long double version of trunc(); it takes a long double argument and returns a long double result.

truncw() is an extended version of trunc(); it takes an extended argument and returns an extended result.

truncq() is equivalent to truncl() on HP-UX systems.

USAGE

To use these functions, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE options.

To use (for Integrity servers) truncw() or truncq(), compile also with the -fpwidetypes option.

To use these functions, make sure your program includes <math.h>. Link in the math library by specifying -lm on the compiler or linker command line.

For more information, see the HP-UX floating-point guide for HP Integrity servers at the following site: http://www.hp.com/go/fp.

RETURN VALUE

If x is ±INFINITY or ±zero, trunc() returns x.

If x is NaN, trunc() returns NaN.

trunc() may raise the inexact exception if x is non-integral and finite.

ERRORS

No errors are defined.

STANDARDS CONFORMANCE

trunc(), truncf(), truncl() : ISO/IEC C99 (including Annex F, ``IEC 60559 floating-point arithmetic'')