Update type-conversion documentation for long-ago changes.

This example wasn't updated when we changed the behavior of bpcharlen()
in 8.0, nor when we changed the number of parameters taken by the bpchar()
cast function in 7.3.  Per report from lsliang.

diff --git a/doc/src/sgml/typeconv.sgml b/doc/src/sgml/typeconv.sgml
index fffd2aa9858946c8ba0cfece9607bad22c0090e9..d97785d15a2a38e86040469cf7fcee9674ca490e 100644 (file)
--- a/doc/src/sgml/typeconv.sgml
+++ b/doc/src/sgml/typeconv.sgml
@@ -758,9 +758,11 @@ cast is a cast from that type to itself.  If one is found in the
 pg_cast catalog, apply it to the expression before storing
 into the destination column.  The implementation function for such a cast
 always takes an extra parameter of type integer, which receives
-the destination column's declared length (actually, its
-atttypmod value; the interpretation of
-atttypmod varies for different data types).  The cast function
+the destination column's atttypmod value (typically its
+declared length, although the interpretation of atttypmod
+varies for different data types), and it may take a third boolean
+parameter that says whether the cast is explicit or implicit.  The cast
+function
 is responsible for applying any length-dependent semantics such as size
 checking or truncation.
 
@@ -772,17 +774,17 @@ checking or truncation.
 <type>character</type> Storage Type Conversion
 
 
-For a target column declared as character(20) the following statement
-ensures that the stored value is sized correctly:
+For a target column declared as character(20) the following
+statement shows that the stored value is sized correctly:
 
 
 CREATE TABLE vv (v character(20));
 INSERT INTO vv SELECT 'abc' || 'def';
-SELECT v, length(v) FROM vv;
+SELECT v, octet_length(v) FROM vv;
 
-          v           | length
-----------------------+--------
- abcdef               |     20
+          v           | octet_length
+----------------------+--------------
+ abcdef               |           20
 (1 row)
 
 
@@ -796,7 +798,7 @@ char, the internal name of the character data type) to match the
 column type.  (Since the conversion from text to
 bpchar is binary-coercible, this conversion does
 not insert any real function call.)  Finally, the sizing function
-bpchar(bpchar, integer)> is found in the system catalog
+bpchar(bpchar, integer, boolean)> is found in the system catalog
 and applied to the operator's result and the stored column length.  This
 type-specific function performs the required length check and addition of
 padding spaces.