NTSTATUS trick for NTTIME?
tridge at samba.org
tridge at samba.org
Wed Mar 9 20:38:11 MST 2011
There may be a simpler way to achieve what you want. If we add the
-Wconversion warning to the developer flags then we will get a warning
on mixing of time_t and NTTIME, where NTTIME is typedef to a uint64_t.
I wrote a little test here:
and I get these warnings from the test:
nttime_test.c:25: warning: conversion to ‘time_t’ from ‘NTTIME’ may change the sign of the result
nttime_test.c:27: warning: conversion to ‘NTTIME’ from ‘time_t’ may change the sign of the result
nttime_test.c:33: warning: conversion to ‘NTTIME’ from ‘time_t’ may change the sign of the result
nttime_test.c:35: warning: conversion to ‘time_t’ from ‘NTTIME’ may change the sign of the result
I also think the structure approach may not win us as much as it does
for NTSTATUS. The NTSTATUS type is mostly used as a return value, but
NTTIME is often used as a pointer argument. When used as a pointer
argument, you only get a warning, not a compile error, which means we
aren't actually better off than we are with -Wconversion. For
functions that return a time, we would get a compile error rather than
a warning by using the structure, but I'm not sure the difference is
worth the overhead of all the accessor functions.
What would you think about trying the low-impact approach of adding
-Wconversion ? The disadvantage would be that we get a whole lot of
warnings from existing code. I've tried this on a S4 build, and it
does add a lot of warnings, but it looks like many of the warnings are
actually things we should fix.
We could also potentially teach waf to consider gcc -Wconverion
warnings as fatal if the warning contains the words 'NTTIME' and
'time_t'. We could do that with the autoconf build too, with a wrapper
Alternatively, we could add rules to autobuild to consider a set of
warnings (defined via regular expressions) as fatal, and to refuse the
push to master if there is a NTTIME/time_t warning. That may be the
simplest solution, and potentially we could have -Wconversion only on
in autobuild, to reduce the noise of /usr/include warnings for most
developers (depending on how many there are).
The autobuild approach also would work for a lot of other warning
types, and would be a step towards what we discussed earlier of
autobuild requiring that all commits not increase the warning count.
btw, this relies on the fact that time_t is signed on Linux, whereas
NTTIME is unsigned. I think that we don't have to worry about
portability of the warning though, as enough of us (all of us?)
develop on Linux, so we'll easily catch the errors.
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