change RECIPEPREFIX to space work only with simple expansion

Hi community, I tried to change RECIPEPREFIX to space.  It works with simple variable expansion but not recursive expansion, as shown in the first three assignments to it. I ever thought that the simple expansion gurantees that it happens  before enter recipe. But in the manual 6.14, it present

why make clean triggers other rules

Hi community, 1.  Why will the rule for `.d` dependency file be triggered when I do `make clean`? Why it tries to stop me from deleting the temporary `.d` file? I define an explicit pattern rule for `.o` object file,  and there is also an implicit rule for it. Why rule for `.o` object file is

Re: why make clean triggers other rules

Thanks Paul, I have been following your article https://make.mad-scientist.net/papers/advanced-auto-dependency-generation/ and put ` CPPFLAGS += -MMD ` in my makefile. And this works. I have been so confused for years everytime when I read the example in manual section 4.14 `Generating Prer

Re: why make clean triggers other rules

Thanks Paul! Correct some of my misunderstanding: ``` %.d: %.c set -e; rm -f $@; \ $(CC) -M $(CPPFLAGS) $< > $@.; \ sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@. > $@; \ rm -f $@. ``` the .d file depends on `.c` source file as stated in rule ` %.d: %.c `. the sed command puts the `.