Makefile: If target name contains colon (:) (lemmy.ml)

submitted 2 years ago by [email protected] to c/[email protected]

6 comments fedilink hide all child comments

cross-posted from: https://lemmy.ml/post/3229278

Suppose I've got a simple #Makefile w/ a few URLs that I'd like to process as dynamic targets.

For example here is a not working snippet:
.DEFAULT_GOAL := all

#####
URLS  = https://foo.example.com
URLS += https://bar.example.com
URLS += https://www.example.org

#####
% :
	@echo the url is $(*)

#####
.PHONY : all
all : $(URLS)
It fails w/

*** target pattern contains no '%'

I believe that's b/c of the character : being part of URLS which confuses Make after expansion (order o

As a workaround, I've removed https:// from all URLs. For example this works:
URLS = foo.example.com
URLS += bar.example.com
I know Make generally doesn't play well w/ targets w/ space or colon in the name but I wonder if the above is the best I can do. What do you think?

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[-] [email protected] 10 points 2 years ago* (last edited 2 years ago)

You can escape the :

URLS  = https\://foo.example.com
URLS += https\://bar.example.com
URLS += https\://www.example.org

[-] [email protected] 5 points 2 years ago

Ah...this explains why it works: https://savannah.gnu.org/bugs/?712#comment16

It's a new feature \o/

#TIL

[-] [email protected] 1 points 2 years ago

@pnutzh4x0r @[email protected] I'm not at my desk now but I doubt it will work. Make has no notion of escaping as far as I know.

[-] [email protected] 1 points 2 years ago

I just tried it with GNU make 4.3 and it worked.

[-] [email protected] 2 points 2 years ago

Oh, it works 🎉 Thank you!

For posterity here's a complete example:

foo\:bar :
	@echo $(@)

and then

$ make foo:bar
foo:bar

Though, TBH, I don't understand how this works 🤦‍♂️ I need to look into Make docs.

[-] [email protected] 2 points 2 years ago

I didn't try yet: https://www.cmcrossroads.com/article/gnu-make-escaping-walk-wild-side

colon := :
$(colon) := :
url := https$(:)//something

this post was submitted on 12 Aug 2023

31 points (97.0% liked)

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