Add comment on C locale test for upper/lower/initcap().

diff --git a/src/backend/utils/adt/oracle_compat.c b/src/backend/utils/adt/oracle_compat.c
index ee59ae60eef9244f9c0a43ff7e86a23a26292d84..d0d1fc5fecfeb38a8d6b93961e8dc7494c27944d 100644 (file)
--- a/src/backend/utils/adt/oracle_compat.c
+++ b/src/backend/utils/adt/oracle_compat.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.59 2005/03/16 01:49:10 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.60 2005/05/07 15:18:17 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -167,7 +167,11 @@ Datum
 lower(PG_FUNCTION_ARGS)
 {
 #ifdef USE_WIDE_UPPER_LOWER
-   /* use wide char code only when max encoding length > 1 and ctype != C */
+   /*
+    *  Use wide char code only when max encoding length > 1 and ctype != C.
+    *  Some operating systems fail with multi-byte encodings and a C locale.
+    *  Also, for a C locale there is no need to process as multibyte.
+    */
    if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
    {
        text       *string = PG_GETARG_TEXT_P(0);
@@ -229,7 +233,11 @@ Datum
 upper(PG_FUNCTION_ARGS)
 {
 #ifdef USE_WIDE_UPPER_LOWER
-   /* use wide char code only when max encoding length > 1 and ctype != C */
+   /*
+    *  Use wide char code only when max encoding length > 1 and ctype != C.
+    *  Some operating systems fail with multi-byte encodings and a C locale.
+    *  Also, for a C locale there is no need to process as multibyte.
+    */
    if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
    {
        text       *string = PG_GETARG_TEXT_P(0);
@@ -294,7 +302,11 @@ Datum
 initcap(PG_FUNCTION_ARGS)
 {
 #ifdef USE_WIDE_UPPER_LOWER
-   /* use wide char code only when max encoding length > 1 and ctype != C */
+   /*
+    *  Use wide char code only when max encoding length > 1 and ctype != C.
+    *  Some operating systems fail with multi-byte encodings and a C locale.
+    *  Also, for a C locale there is no need to process as multibyte.
+    */
    if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
    {
        text       *string = PG_GETARG_TEXT_P(0);