mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-23 12:51:06 +00:00
94 lines
2.4 KiB
ReStructuredText
94 lines
2.4 KiB
ReStructuredText
PR_dtoa
|
|
=======
|
|
|
|
Converts a floating point number to a string.
|
|
|
|
|
|
Syntax
|
|
------
|
|
|
|
.. code::
|
|
|
|
#include <prdtoa.h>
|
|
|
|
PRStatus PR_dtoa(
|
|
PRFloat64 d,
|
|
PRIntn mode,
|
|
PRIntn ndigits,
|
|
PRIntn *decpt,
|
|
PRIntn *sign,
|
|
char **rve,
|
|
char *buf,
|
|
PRSize bufsz);
|
|
|
|
|
|
Parameters
|
|
~~~~~~~~~~
|
|
|
|
The function has these parameters:
|
|
|
|
``d``
|
|
The floating point number to be converted to a string.
|
|
``mode``
|
|
The type of conversion to employ.
|
|
``ndigits``
|
|
The number of digits desired in the output string.
|
|
``decpt``
|
|
A pointer to a memory location where the runtime will store the
|
|
offset, relative to the beginning of the output string, of the
|
|
conversion's decimal point.
|
|
``sign``
|
|
A location where the runtime can store an indication that the
|
|
conversion was of a negative value.
|
|
``*rve``
|
|
If not ``NULL`` this location is set to the address of the end of the
|
|
result.
|
|
``buf``
|
|
The address of the buffer in which to store the result.
|
|
``bufsz``
|
|
The size of the buffer provided to hold the result.
|
|
|
|
Results
|
|
~~~~~~~
|
|
|
|
The principle output is the null-terminated string stored in ``buf``. If
|
|
``rve`` is not ``NULL``, ``*rve`` is set to point to the end of the
|
|
returned value.
|
|
|
|
|
|
Description
|
|
-----------
|
|
|
|
This function converts the specified floating point number to a string,
|
|
using the method specified by ``mode``. Possible modes are:
|
|
|
|
``0``
|
|
Shortest string that yields ``d`` when read in and rounded to
|
|
nearest.
|
|
``1``
|
|
Like 0, but with Steele & White stopping rule. For example, with IEEE
|
|
754 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.
|
|
``4,5,8,9``
|
|
Same as modes 2 and 3, but using\ *left to right* digit generation.
|
|
``6-9``
|
|
Same as modes 2 and 3, but do not try fast floating-point estimate
|
|
(if applicable).
|
|
``all others``
|
|
Treated as mode 2.
|
|
|
|
Upon return, the buffer specified by ``buf`` and ``bufsz`` contains the
|
|
converted string. Trailing zeros are suppressed. Sufficient space is
|
|
allocated to the return value to hold the suppressed trailing zeros.
|
|
|
|
If the input parameter ``d`` is\ *+Infinity*,\ *-Infinity* or\ *NAN*,
|
|
``*decpt`` is set to 9999.
|