diff options
| -rw-r--r-- | doc/src/sgml/xfunc.sgml | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index d9afd3be4d0..b5d4b10c725 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -2239,9 +2239,9 @@ PG_FUNCTION_INFO_V1(funcname); <para> In a version-1 function, each actual argument is fetched using a <function>PG_GETARG_<replaceable>xxx</replaceable>()</function> - macro that corresponds to the argument's data type. In non-strict + macro that corresponds to the argument's data type. (In non-strict functions there needs to be a previous check about argument null-ness - using <function>PG_ARGNULL_<replaceable>xxx</replaceable>()</function>. + using <function>PG_ARGISNULL()</function>; see below.) The result is returned using a <function>PG_RETURN_<replaceable>xxx</replaceable>()</function> macro for the return type. @@ -2404,14 +2404,6 @@ CREATE FUNCTION concat_text(text, text) RETURNS text </para> <para> - At first glance, the version-1 coding conventions might appear to be just - pointless obscurantism, over using plain <literal>C</literal> calling - conventions. They do however allow to deal with <literal>NULL</literal>able - arguments/return values, and <quote>toasted</quote> (compressed or - out-of-line) values. - </para> - - <para> The macro <function>PG_ARGISNULL(<replaceable>n</replaceable>)</function> allows a function to test whether each input is null. (Of course, doing this is only necessary in functions not declared <quote>strict</quote>.) @@ -2426,6 +2418,14 @@ CREATE FUNCTION concat_text(text, text) RETURNS text </para> <para> + At first glance, the version-1 coding conventions might appear + to be just pointless obscurantism, compared to using + plain <literal>C</literal> calling conventions. They do however allow + us to deal with <literal>NULL</literal>able arguments/return values, + and <quote>toasted</quote> (compressed or out-of-line) values. + </para> + + <para> Other options provided by the version-1 interface are two variants of the <function>PG_GETARG_<replaceable>xxx</replaceable>()</function> |