docs: Summarise directory reference syntaxes

[subdirmk.git] / README

diff --git a/README b/README
index f481157e315c3c3c09babbccfec9805edd78e4e1..5897e308644050ec8006fe42e830816ed03f0fb2 100644 (file)
--- a/README
+++ b/README
@@ -138,6 +138,19 @@ If you `include subdirmk/regen.mk', dependency management and
 automatic regeneration for all of this template substitution, and for
 config.status etc. is done for you.
 
 automatic regeneration for all of this template substitution, and for
 config.status etc. is done for you.
 

+Summary of directory reference syntaxes
+---------------------------------------
+
+                  In source tree             In build tree
+                  Relative     Absolute      Relative  Absolute
+
+                                             &file     $(abs)/&file
+ This directory   &^/file      &~/file       &/file    $(abs)/&/file
+                  & ^ f g h    & ~ f g h     & f g h
+
+ Top level        $(ts)/file   $(ats)/file   file      $(abs)/file
+                                             f g h
+

 Substitution syntax
 -------------------
 
 Substitution syntax
 -------------------
 


@@ -282,7 +295,10 @@ You can convert your project incrementally.  Start with the top-level
 Makefile.in and rename it to Subdir.sd.mk, and add the appropriate
 stuff to configure.ac, and fix everything up.  Leave the existing
 $(MAKE) -C for your existing subdirectories alone.  Then you can
 Makefile.in and rename it to Subdir.sd.mk, and add the appropriate
 stuff to configure.ac, and fix everything up.  Leave the existing
 $(MAKE) -C for your existing subdirectories alone.  Then you can

-convert individual subdirectories, or classes of subdirectories.
+convert individual subdirectories, or classes of subdirectories, at
+your leisure.  (You must be /sure/ that each subdirectory will be
+entered only once at a time, but your existing recursive make descent
+system should already do that or you already have concurrency bugs.)

 
 Aside from this, be very wary of any invocation of $(MAKE) anywhere.
 This is a frequent source of concurrency bugs in recursive make build
 
 Aside from this, be very wary of any invocation of $(MAKE) anywhere.
 This is a frequent source of concurrency bugs in recursive make build