[tz] [PROPOSED] Remove old Y2K code
abbotti at mev.co.uk
Wed Jun 14 10:11:07 UTC 2017
On 13/06/17 20:47, Paul.Koning at dell.com wrote:
>> On Jun 13, 2017, at 2:17 PM, Jonathan Lennox <lennox at cs.columbia.edu> wrote:
>> On Monday, June 12 2017, "Paul Eggert" wrote to "Brian.Inglis at SystematicSw.ab.ca, Time zone mailing list" saying:
>>> Perhaps you're right, I was too hasty. I brought back that code under
>>> the name you suggested, by installing the attached.
>>> + Y2K runtime checks are no longer enabled by default. Add
>>> + -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
>>> + adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
>>> + to disable them. (New name suggested by Brian Inglis.)
>> Since DEPRECATE_TWO_DIGIT_YEARS is used in an if statement, shouldn't this
>> be -DDEPRECATE_TWO_DIGIT_YEARS=true ? Otherwise it expands to
>> if ( && warn != IN_NONE ...
>> which obviously won't compile.
> Not so, because -DFOO is equivalent to -DFOO=1 .
Yes, although technically this is compiler (or precompiler) behavior,
not part of any C standard (since it only concerns the language).
The comments for the '-D' options in Makefile mostly seem to follow the
style of omitting the default '=1' (as it assumes POSIX style C compiler
options are being used), except for the cases where '=1' is one of two
or more documented values (for example, in the comments for 'HAVE_TZNAME').
Perhaps a note could be added to the comments in the Makefile to make it
clear that it is assuming that '-DFOO' is equivalent to '-DFOO=1', and
that '-DFOO=bar' defines a macro with the given replacement, although I
guess anyone porting the Makefile and compiler options ought to have a
passing acquaintance with POSIX conventions.
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti at mev.co.uk> )=-
-=( Web: http://www.mev.co.uk/ )=-
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