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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2021-09-06 11:43:44 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2021-09-06 11:43:44 -0400 |
| commit | 89dba59590fdd03799a47daf8019890d4324fbcf (patch) | |
| tree | 0321a2b360059809b7e6709542b253ae556742df | |
| parent | 388e71af880d579212c2489686903c2cfdea9032 (diff) | |
| download | postgresql-89dba59590fdd03799a47daf8019890d4324fbcf.tar.gz postgresql-89dba59590fdd03799a47daf8019890d4324fbcf.zip | |
Fix actively-misleading comments about the contents of struct pg_tm.
pgtime.h documented the PG interpretation of tm_mon right alongside
the POSIX interpretation of tm_year, with no hint that neither
comment was correct throughout our code.
Perhaps someday we ought to switch to using two separate struct
definitions to provide a clearer indication of which semantics are
in use where. But I fear the tedium-versus-safety-gain tradeoff
would not be very good.
Discussion: https://postgr.es/m/CAJ7c6TOMG8zSNEZtCn5SPe+cCk3Lfxb71ZaQwT2F4T7PJ_t=KA@mail.gmail.com
| -rw-r--r-- | src/include/pgtime.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/include/pgtime.h b/src/include/pgtime.h index 28bd27e7f79..92350527f65 100644 --- a/src/include/pgtime.h +++ b/src/include/pgtime.h @@ -22,14 +22,21 @@ typedef int64 pg_time_t; +/* + * CAUTION: the IANA timezone library (src/timezone/) follows the POSIX + * convention that tm_mon counts from 0 and tm_year is relative to 1900. + * However, Postgres' datetime functions generally treat tm_mon as counting + * from 1 and tm_year as relative to 1 BC. Be sure to make the appropriate + * adjustments when moving from one code domain to the other. + */ struct pg_tm { int tm_sec; int tm_min; int tm_hour; int tm_mday; - int tm_mon; /* origin 1, not 0! */ - int tm_year; /* relative to 1900 */ + int tm_mon; /* see above */ + int tm_year; /* see above */ int tm_wday; int tm_yday; int tm_isdst; |