Wednesday, July 27, 2011

GNU Make Recursive Wildcard Function

A reader wrote in to ask me about an old message in a mailing list where I'd defined a recursive version of GNU Make's wildcard function.

Unfortunately, there's an error in that message and the correct function is as follows:
rwildcard=$(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2)
  $(filter $(subst *,%,$2),$d))
Usage is as follows. First, all C files in the current directory (or below).
$(call rwildcard,,*.c)
Then all C files in /tmp:
$(call rwildcard,/tmp/,*.c)
Multiple patterns can be used. Here are all C and H files:
$(call rwildcard,/tmp/,*.c *.h)

6 comments:

deadbok said...

Thank you for posting this, I could not wrap my head around it myself.

deadbok said...

Thank you, this post saved me a lot of headaches.

Alex Cohn said...

Thanks a lot!

Alex Cohn said...

Thanks a lot!

Michel Grosjean said...

Many thanks for this, I was afraid I might have to do something very ugly, but thanks to you I guess I won't :D

Peter Vranken said...

A minor change of the code makes it capabale of searching in a list of base directories:
rwildcard = $(foreach d,$(wildcard $(addsuffix *,$(1))),$(call rwildcard,$(d)/,$(2)) $(filter $(subst *,%,$(2)),$(d)))

The $(addsuffix *,$(1)) instead of $(1)* expands a list of directories in the root invocation into directory candidates for further procesing.

Just a tip: A $(strip ...) around the complete RHS makes it better maintainable in case you want to print the output.