FESETPREC(3M) Mathematical Library Functions FESETPREC(3M)

NAME

fesetprec, fegetprec - control floating point rounding precision
modes

SYNOPSIS

c99 [ flag... ] file... -lm [ library... ]
#include <fenv.h>

int fesetprec(int prec);


int fegetprec(void);

DESCRIPTION

The IEEE 754 standard defines rounding precision modes for systems
that always deliver intermediate results to destinations in extended
double precision format. These modes allow such systems to deliver
correctly rounded single and double precision results (in the absence
of underflow and overflow) with only one rounding.


The fesetprec() function sets the current rounding precision to the
precision specified by prec, which must be one of the following
values defined in <fenv.h>:

FE_FLTPREC
round to single precision


FE_DBLPREC
round to double precision


FE_LDBLPREC
round to extended double precision


The default rounding precision when a program starts is FE_LDBLPREC.


The fegetprec() function returns the current rounding precision.

RETURN VALUES

The fesetprec() function returns a non-zero value if the requested
rounding precision is established and 0 otherwise.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+----------------------------------------------------------+
|ATTRIBUTE TYPE ATTRIBUTE VALUE |
|Architecture Intel (see below) |
|Availability SUNWlibms |
|Interface Stability Stable |
|MT-Level MT-Safe |
+----------------------------------------------------------+


These functions are not available on SPARC systems because SPARC
processors deliver intermediate results to destinations in single or
double format as determined by each floating point instruction.

SEE ALSO

fegetenv(3M), fesetround(3M), attributes(7)


Numerical Computation Guide

SunOS 5.11 July 12, 2006 FESETPREC(3M)