Doc: document the tie-breaking behavior of the round() function.
Back-patch to v13; the table layout in older branches is unfriendly
to adding such details.
Laurenz Albe
Discussion:
@@ -1568,7 +1568,10 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
<returnvalue>double precision</returnvalue>
</para>
<para>
- Rounds to nearest integer
+ Rounds to nearest integer. For <type>numeric</type>, ties are
+ broken by rounding away from zero. For <type>double precision</type>,
+ the tie-breaking behavior is platform dependent, but
+ <quote>round to nearest even</quote> is the most common rule.
</para>
<para>
<literal>round(42.4)</literal>
@@ -1583,7 +1586,7 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</para>
<para>
Rounds <parameter>v</parameter> to <parameter>s</parameter> decimal
- places
+ places. Ties are broken by rounding away from zero.
</para>
<para>
<literal>round(42.4382, 2)</literal>
