low-level C routines for numeric conversions.

Index: conversion; numbers; ASCII

INTERFACE CConvert;

FROM Ctypes IMPORT double, int, int_star, char_star, char_star_star;

<* EXTERNAL m3_strtod *>
PROCEDURE strtod (nptr: ADDRESS; VAR eptr: ADDRESS): LONGREAL;

Returns a nearest machine number to the input decimal string (or sets errno to ERANGE). With IEEE arithmetic, ties are broken by the IEEE round-even rule. Otherwise ties are broken by biased rounding (add half and chop).

<* EXTERNAL m3_dtoa *>
PROCEDURE dtoa (d: double;  mode: int;  ndigits: int;  decpt: int_star;
                sign: int_star;  rve: char_star_star): char_star;

Converts a C double to an ASCII string.

mode: 0 ==> shortest string that yields d when read in and rounded to nearest. 1 ==> like 0, but with Steele & White stopping rule; e.g. with IEEE P754 arithmetic , mode 0 gives 1e23 whereas mode 1 gives 9.999999999999999e22. 2 ==> max(1,ndigits) significant digits. This gives a return value similar to that of ecvt, except that trailing zeros are suppressed. 3 ==> through ndigits past the decimal point. This gives a return value similar to that from fcvt, except that trailing zeros are suppressed, and ndigits can be negative. 4,5 ==> similar to 2 and 3, respectively, but (in round-nearest mode) with the tests of mode 0 to possibly return a shorter string that rounds to d. With IEEE arithmetic and compilation with -DHonor_FLT_ROUNDS, modes 4 and 5 behave the same as modes 2 and 3 when FLT_ROUNDS != 1. 6-9 ==> Debugging modes similar to mode - 4: don't try fast floating-point estimate (if applicable).

Values of mode other than 0-9 are treated as mode 0.

Sufficient space is allocated to the return value to hold the suppressed trailing zeros.

<* EXTERNAL m3_freedtoa *>
PROCEDURE freedtoa (s: char_star);

Must be used to free values s returned by dtoa.

PROCEDURE Acquire (n: INTEGER);
PROCEDURE Release (n: INTEGER);

END CConvert.