By default, Newlib uses a huge object of type struct _reent to store
thread-specific data. This object is returned by __getreent() if the
__DYNAMIC_REENT__ Newlib configuration option is defined.
The reentrancy structure contains for example errno and the standard input,
output, and error file streams. This means that if an application only uses
errno it has a dependency on the file stream support even if it does not use
it. This is an issue for lower end targets and applications which need to
qualify the software according to safety standards (for example ECSS-E-ST-40C,
ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333).
If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct
_reent is replaced by dedicated thread-local objects for each struct _reent
member. The thread-local objects are defined in translation units which use
the corresponding object.
Add a _REENT_CVTBUF() macro to encapsulate access to the _cvtbuf
member of struct reent. This will help to replace the struct
member with a thread-local storage object in a follow up patch.
Add a _REENT_CVTLEN() macro to encapsulate access to the _cvtlen
member of struct reent. This will help to replace the struct
member with a thread-local storage object in a follow-up patch.
In the two helper functions that _dcvt calls for 'f' and 'e' mode, if
there are no digits to display after the decimal point, don't add one.
Signed-off-by: Keith Packard <keithp@keithp.com>
Leading zeros after the decimal point should not count
towards the 'ndigits' limit.
This makes gcvt match glibc and the posix gcvt man page.
Signed-off-by: Keith Packard <keithp@keithp.com>
Even if the number is really small and this means showing *no* digits.
This makes newlib match glibc, and the fcvt posix man page.
Signed-off-by: Keith Packard <keithp@keithp.com>
Matt Joyce
Keith Packard
Yaakov Selkowitz
Jeff Johnston
Christopher Faylor