floating_to_decimal(3C) Standard C Library Functions floating_to_decimal(3C)NAME
floating_to_decimal, single_to_decimal, double_to_decimal,
extended_to_decimal, quadruple_to_decimal - convert floating-point
value to decimal record
SYNOPSIS
#include <floatingpoint.h>
void single_to_decimal(single *px, decimal_mode *pm, decimal_record
*pd, fp_exception_field_type *ps);
void double_to_decimal(double *px, decimal_mode *pm, decimal_record
*pd, fp_exception_field_type *ps);
void extended_to_decimal(extended *px, decimal_mode *pm, decimal_record
*pd, fp_exception_field_type *ps);
void quadruple_to_decimal(quadruple *px, decimal_mode *pm, deci‐
mal_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
(sig)*(pd->ds)*10**(pd->exponent)
is a correctly rounded approximation to *px, where sig is +1 or −1,
depending upon whether pd→sign is 0 or −1. 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 sig‐
nificant 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 the decimal value is
rounded at pm→ndigits digits to the right of the decimal point. For
example, if *px == 12.34 and pm→ndigits == 1, then pd→ds will contain
123 and pd→exponent will be set to −1.
If pm→df == fixed_form and pm→ndigits< 0, then the decimal value is
rounded at −pm→ndigits digits to the left of the decimal point, and
pd→ds is padded with trailing zeros up to the decimal point. For exam‐
ple, if *px == 12.34 and pm→n digits == −1, then pd→ds will contain 10
and pd→exponent will be set to 0.
When pm→df == fixed_form and the value to be converted is large enough
that the resulting string would contain more than DECI‐
MAL_STRING_LENGTH−1 digits, then the string placed in pd→ds is limited
to exactly DECIMAL_STRING_LENGTH-1 digits (by moving the place at which
the value is rounded further left if need be), pd→exponent is adjusted
accordingly and the overflow flag is set in *ps.
pd->more is not used.
The econvert(3C), fconvert(3C), gconvert(3C), printf(3C), and
sprintf(3C) functions all use double_to_decimal().
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOeconvert(3C), fconvert(3C), gconvert(3C), printf(3C), sprintf(3C),
attributes(5)SunOS 5.10 7 Jun 2005 floating_to_decimal(3C)