On 10/2/19 11:02 AM, Tom Lane wrote:
Mark Dilger <hornschnor...@gmail.com> writes:
On 10/2/19 8:46 AM, Tom Lane wrote:
Right. I think that in general it's bad practice for an initializer
to not specify all fields/elements of the target.
There are numerous locations in the code that raise warnings when
-Wmissing-field-initializers is handed to gcc. See, for example,
src/backend/utils/adt/formatting.c where
static const KeyWord NUM_keywords[]
is initialized, and the code comment above that disclaims the need to
initialize is_digit and date_mode. Are you proposing cleaning up all
such incomplete initializations within the project?
Hmm. Maybe it's worth doing as a code beautification effort, but
I'm not volunteering. At the same time, I wouldn't like to make a
change like this, if it introduces dozens/hundreds of new cases.
I understand that your INIT_ALL_ZEROS macro does nothing to change
whether -Wmissing-field-initializers would raise a warning.
Not sure --- the name of that option suggests that maybe it only
complains about omitted *struct fields* not omitted *array elements*.
With gcc (Debian 8.3.0-6) 8.3.0
int foo[6] = {0, 1, 2};
does not draw a warning when compiled with this flag.
If it does complain, is there any way that we could extend the macro
to annotate usages of it to suppress the warning?
Neither initializing a struct with {0} nor with INIT_ALL_ZEROS draws a
warning either, with my gcc. There are reports online that older
versions of the compiler did, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36750
but I don't have an older version to test with just now.
Note that initializing a multi-element struct with {1} does still draw a
warning, and reading the thread above suggests that gcc made a specific
effort to allow initialization to {0} to work without warning as a
special case.
So your proposal for using INIT_ALL_ZEROS is probably good with
sufficiently new compilers, and I'm generally in favor of the proposal,
but I don't think the decree you propose can work unless somebody cleans
up all these other cases that I indicated in my prior email.
(I'm sitting on a few patches until v12 goes out the door from some
conversations with you several months ago, and perhaps I'll include a
patch for this cleanup, too, when time comes for v13 patch sets to be
submitted. My past experience submitting patches shortly before a
release was that they get ignored.)
mark
