Create directories using make file

Question

I\'m a very new to makefiles and i want to create directories using makefile. My project directory is like this

+--Project  
   +--output  
   +--source  
           


        

Answer 1

Or, KISS.

DIRS=build build/bins

... 

$(shell mkdir -p $(DIRS))

This will create all the directories after the Makefile is parsed.

Answer 2

I've just come up with a fairly reasonable solution that lets you define the files to build and have directories be automatically created. First, define a variable ALL_TARGET_FILES that holds the file name of every file that your makefile will be build. Then use the following code:

define depend_on_dir
$(1): | $(dir $(1))

ifndef $(dir $(1))_DIRECTORY_RULE_IS_DEFINED
$(dir $(1)):
    mkdir -p $$@

$(dir $(1))_DIRECTORY_RULE_IS_DEFINED := 1
endif
endef

$(foreach file,$(ALL_TARGET_FILES),$(eval $(call depend_on_dir,$(file))))

Here's how it works. I define a function depend_on_dir which takes a file name and generates a rule that makes the file depend on the directory that contains it and then defines a rule to create that directory if necessary. Then I use foreach to call this function on each file name and eval the result.

Note that you'll need a version of GNU make that supports eval, which I think is versions 3.81 and higher.

Answer 3

given that you're a newbie, I'd say don't try to do this yet. it's definitely possible, but will needlessly complicate your Makefile. stick to the simple ways until you're more comfortable with make.

that said, one way to build in a directory different from the source directory is VPATH; i prefer pattern rules