diff --git a/src/include/c.h b/src/include/c.h
index 7752e1ae02..b7a1e11268 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/c.h,v 1.188 2005/07/18 15:53:28 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/c.h,v 1.189 2005/07/21 15:16:27 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -630,6 +630,7 @@ typedef NameData *Name;
 #define MemSet(start, val, len) \
 	do \
 	{ \
+		/* must be void* because we don't know if it is integer aligned yet */ \
 		void   *_vstart = (void *) (start); \
 		int		_val = (val); \
 		Size	_len = (len); \
diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index ae2ef56e0e..35221d5f1d 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.49 2005/07/21 04:48:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.50 2005/07/21 15:16:27 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,6 +63,12 @@ typedef struct
 /* in both timestamp.h and ecpg/dt.h */
 #define DAYS_PER_YEAR	365.25	/* assumes leap year every four years */
 #define MONTHS_PER_YEAR	12
+/*
+ *	DAYS_PER_MONTH is very imprecise.  The more accurate value is
+ *	365.25/12 = 30.4375, or '30 days 10:30:00'.  Right now we only
+ *	return an integral number of days, but someday perhaps we should
+ *	also return a 'time' value to be used as well.
+ */
 #define DAYS_PER_MONTH	30		/* assumes exactly 30 days per month */
 #define HOURS_PER_DAY	24		/* assume no daylight savings time changes */
 
diff --git a/src/interfaces/ecpg/pgtypeslib/dt.h b/src/interfaces/ecpg/pgtypeslib/dt.h
index 14fbd3c987..01b44fb27a 100644
--- a/src/interfaces/ecpg/pgtypeslib/dt.h
+++ b/src/interfaces/ecpg/pgtypeslib/dt.h
@@ -219,6 +219,12 @@ do { \
 /* in both timestamp.h and ecpg/dt.h */
 #define DAYS_PER_YEAR	365.25	/* assumes leap year every four years */
 #define MONTHS_PER_YEAR	12
+/*
+ *	DAYS_PER_MONTH is very imprecise.  The more accurate value is
+ *	365.25/12 = 30.4375, or '30 days 10:30:00'.  Right now we only
+ *	return an integral number of days, but someday perhaps we should
+ *	also return a 'time' value to be used as well.
+ */
 #define DAYS_PER_MONTH	30		/* assumes exactly 30 days per month */
 #define HOURS_PER_DAY	24		/* assume no daylight savings time changes */