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
+Path construction &-expansions, meanings summary:
+
+ In build tree In source tree
+ This directory just & &,
+ Top level &. implies absolute &;
+
+Adding `@' means "absolute path". This is not needed with &. because
+there is never any need to use &. since it would expand to nothing.
+`/' terminates the escape (needed if the next thing is not a lowercase
+character, or space). `=' means "just the value, no /". Space starts
+multi-word processing.
+
+ Recommended In build tree In source tree
+ when Relative Absolute Relative Absolute
+
+ This lc &file &@file &,file &@,file
+ directory any &/file &@/file &,/file &@,/file
+ several & f g h &@ f g h &, f g h &^, f g h
+
+ Top lc &.file &;file &@;file
+ level any file &./file &;/file &@;/file
+ .mk.in file $(abs)/file $(src)/file $(abs_src)/file
+ several f g h &. f g h &; f g h &@; f g h
+ &@. file
+ &@. f g h
Substitution syntax
-------------------
&^ => $(top_srcdir)/sub/dir or $(top_srcdir)
&~ => $(abs_top_srcdir)/sub/dir or $(abs_top_srcdir)
+In general:
+ ^ filenames in source tree rather than build tree
+ ~ filenames are absolute rather than relative
+ @ filenames do not contain subdir (useful with the above)
+
&& => && for convenience in shell runes
\& => & general escaping mechanism