Chapter Contents

Previous

Next
_ldexp

_ldexp



Fast Implementation of ldexp

Portability: SAS/C extension


SYNOPSIS
DESCRIPTION
RETURN VALUE
DIAGNOSTICS
PORTABILITY
IMPLEMENTATION
RELATED FUNCTIONS
SEE ALSO


SYNOPSIS

#include <lcmath.h>

double _ldexp (double y, int i);


DESCRIPTION

_ldexp calculates y * 2i. It is almost identical to ldexp but it is faster because no error checking is performed.


RETURN VALUE

_ldexp returns the value of type double that results from the calculation.


DIAGNOSTICS

_ldexp generates the SIGFPOFL or SIGFPUFL signal if an error occurs.


PORTABILITY

_ldexp is not portable.


IMPLEMENTATION

_ldexp is implemented as a built-in function unless it is undefined by an #undef statement.

The difference between ldexp and _ldexp is that _ldexp does not check for erroneous arguments, so an ABEND OCC or OCD occurs if the arguments are invalid. Because _ldexp avoids error checking, it is significantly faster than ldexp .


RELATED FUNCTIONS

ldexp


SEE ALSO


Chapter Contents

Previous

Next

Top of Page

Copyright © 2001 by SAS Institute Inc., Cary, NC, USA. All rights reserved.