Makefile processing files with same extension -

this seems related how write makefile target , source files have same extension?. in question extensions same, input , output files seem in same directory , filenames being conditionally renamed.

i have large collection of .txt files in ../src/ need processed, , dumped ./ (which directory called target/) txt files of same name. want use make, files in ../src/ have been changed updated in ./. prototype working before put real code in.

my makefile in ./ follows:

dir = ../src inputs = $(wildcard $(dir)/*.txt) outputs = $(patsubst $(dir)/%.txt,%.txt,$(inputs))  all: $(outputs)  .phony: $(inputs)  check:     @echo "dir = $(dir)"     @echo "inputs = $(inputs)"     @echo "outputs = $(outputs)"  %.txt: $(dir)/%.txt     sed -e "s/test/cat/g" "$<" > $@ 

for now, contents of ../src/ test1.txt , test2.txt. makefile stands now, running make test2.txt generates file expected.

target/ $ make test2.txt sed -e "s/test/cat/g" "../src/test2.txt" > test2.txt 

running make check shows inputs , outputs correctly.

target/ $ make check dir = ../src inputs = ../src/test1.txt ../src/test2.txt outputs = test1.txt test2.txt 

if run make all, generates every file, every time. expected .phony $(inputs) line in there.

if remove .phony $(inputs) target, make gets bound in trying find target make ../src/test1.txt , keeps prefixing $(dir) in front of until makes long of filename , gives up.

make: stat: ../src/../src/../src/ [repeat few pages] ../src/../src/test1.txt: file name long make: stat: ../src/../src/../src/ [repeat few pages] ../src/../src/../src/test1.txt: file name long make: *** no rule make target `../src/../src/../src/[repeat]../src/../src/test1.txt', needed `../src/[repeat]../src/../src/test1.txt'.  stop. 

it never processing test2.txt.

---

as drafting this, had idea remove ../ dir, , relocate makefile parent both src/ , target/. approach seems work, isn't ideal. there chain of these makefiles, each pulling 1 directory another.

is there way keep makefile in 'target/' along generated destination files, , base destination files off of in relative path?

replace

%.txt: $(dir)/%.txt 

with:

${curdir}/%.txt: $(dir)/%.txt 

this way %.txt not match .txt file in directory. in other words, limit rule's scope files in ${curdir}/ , prevents endless recursion.

see §10.5.4 how patterns match more details.

it practice avoid relative paths:

dir = $(abspath ../src)