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

#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,
 decimal_record *pd, fp_exception_field_type *ps);

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 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 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 example, 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 DECIMAL_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().

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

ATTRIBUTE TYPE ATTRIBUTE VALUE

MT-Level MT-Safe

econvert (3C), fconvert (3C), gconvert (3C), printf (3C), sprintf (3C), attributes (7)