Mention dependency problems caused by pgrminclude on include files.

diff --git a/src/tools/pginclude/README b/src/tools/pginclude/README
index ac6cd7edfe23dae99d2a0507e26572a5cf97292e..35f8220526a4c3322f6150f46e920d7af1fb92db 100644 (file)
--- a/src/tools/pginclude/README
+++ b/src/tools/pginclude/README
@@ -13,7 +13,7 @@ pgrminclude [-v]
 pgcheckdefines
                check for #ifdef tests on symbols defined in files that
                weren't included --- this is a necessary sanity check on
-               pgrminclude!
+               pgrminclude
 
 pgdefine       create macro calls for all defines in the file (used by
                the above routines)
@@ -22,9 +22,19 @@ It is also a good idea to sort the pg-specific include files in
 alphabetic order.  This is best done with a text editor. Typical usage
 order would be:
 
-       pgfixinclude  
-       pgcompinclude
-       pgrminclude /src/include
-       pgcompinclude
+       pgfixinclude
+       sort include references
+       run multiple times:
+               pgcompinclude
+               pgrminclude /src/include
        pgrminclude /
        pgcheckdefines
+
+There is a complexity when modifying /src/include.  If include file 1
+includes file 2, and file 2 includes file 3, then when file 1 is
+processed, it needs only file 2, not file 3.  However, if later, include
+file 2 is processed, and file 3 is not needed by file 2 and is removed,
+file 1 might then need to include file 3.  For this reason, the
+pgcompinclude and pgrminclude /src/include steps must be run several
+times until all includes compile cleanly.
+