NAME

floating_to_decimal: single_to_decimal, double_to_decimal, extended_to_decimal - convert floating-point value to decimal record

SYNOPSIS

cc [ flag... ] file ...  -lucb

#include <floatingpoint.h>
void single_to_decimal(px, pm, pd, ps)
single *px ;
decimal_mode *pm;
decimal_record *pd;
fp_exception_field_type *ps;
void double_to_decimal(px, pm, pd, ps)
double *px ;
decimal_mode *pm;
decimal_record *pd;
fp_exception_field_type *ps;
void extended_to_decimal(px, pm, pd, ps)
extended *px ;
decimal_mode *pm;
decimal_record *pd;
fp_exception_field_type *ps;

DESCRIPTION

The floating_to_decimal functions convert the floating-point value at *px into a decimal record at *pd, observing the modes specified in *pm and setting exceptions in *ps. If there are no IEEE exceptions, *ps will be zero. If *px is zero, infinity, or NaN, then only pd->sign and pd->fpclass are set. Otherwise pd->exponent and pd->ds are also set so that

(pd->sign)*(pd->ds)*10**(pd->exponent) is  a  correctly
rounded  approximation  to *px. pd->ds has at least one
and no more than
 DECIMAL_STRING_LENGTH-1 significant digits because one
character  is used to terminate the string with a NULL.
pd->ds is  correctly  rounded  according  to  the  IEEE
rounding  modes  in  pm->rd.  *ps has fp_inexact set if
the result was inexact, and has fp_overflow set if  the
string  result  does  not  fit in pd->ds because of the
limitation     DECIMAL_STRING_LENGTH.       If      pm-
>df==floating_form,  then  pd->ds  always  contains pm-
>ndigits significant digits.  Thus if *px == 12.34  and
pm->ndigits == 8, then pd->ds will contain 12340000 and
pd->exponent will contain  -6.   If  pm->df==fixed_form
and  pm->ndigits  >= 0, then pd->ds always contains pm-
>ndigits after the point and as many digits  as  neces-
sary  before  the point.  Since the latter is not known
in advance, the total  number  of  digits  required  is
returned    in   pd->ndigits;   if   that   number   >=

DECIMAL_STRING_LENGTH, then ds is undefined. pd->exponent always gets -pm->ndigits. Thus if *px == 12.34 and pm->ndigits == 1, then pd->ds gets 123, pd->exponent gets -1, and pd->ndigits gets 3. If pm->df==fixed_form and pm->ndigits < 0, then pm->ds always contains -pm->ndigits trailing zeros; in other words, rounding occurs -pm->ndigits to the left of the decimal point, but the digits rounded away are retained as zeros. The total number of digits required is in pd->ndigits. pd->exponent always gets 0. Thus if *px == 12.34 and pm->ndigits == -1, then pd->ds gets 10, pd->exponent gets 0, and pd->ndigits gets 2. pd->more is not used. econvert(3), fconvert, gconvert, printf(3S), and sprintf, all use double_to_decimal.

SEE ALSO

econvert(3).
printf(3S) in the Programmer's Reference Manual.