?= indicates to set the KDIR variable only if it’s not set/doesn’t have a value. For example: KDIR ?= “foo” KDIR ?= “bar” test: echo $(KDIR) Would print “foo” GNU manual: http://www.gnu.org/software/make/manual/html_node/Setting.html
./configure –prefix=*** Number 1 determines where the package will go when it is installed, and where it will look for its associated files when it is run. It’s what you should use if you’re just compiling something for use on a single host. make install DESTDIR=*** Number 2 is for installing to a temporary directory … Read more
You can use backslash for line continuation. However note that the shell receives the whole command concatenated into a single line, so you also need to terminate some of the lines with a semicolon: foo: for i in `find`; \ do \ all=”$$all $$i”; \ done; \ gcc $$all But if you just want to … Read more
You probably shouldn’t do this; you’re breaking the basic pattern of how Make works. But here it is: action: @echo action $(filter-out $@,$(MAKECMDGOALS)) %: # thanks to chakrit @: # thanks to William Pursell EDIT: To explain the first command, $(MAKECMDGOALS) is the list of “targets” spelled out on the command line, e.g. “action value1 … Read more
Update: If you are using CLion 2020.2, then it already supports Makefiles. If you are using an older version, read on. Even though currently only CMake is supported, you can instruct CMake to call make with your custom Makefile. Edit your CMakeLists.txt adding one of these two commands: add_custom_target add_custom_command When you tell CLion to … Read more
Simple assignment := A simple assignment expression is evaluated only once, at the very first occurrence. For example, if CC :=${GCC} ${FLAGS} during the first encounter is evaluated to gcc -W then each time ${CC} occurs it will be replaced with gcc -W. Recursive assignment = A Recursive assignment expression is evaluated everytime the variable … Read more
The general idea is that make supports (reasonably) minimal rebuilds — i.e., you tell it what parts of your program depend on what other parts. When you update some part of the program, it only rebuilds the parts that depend on that. While you could do this with a shell script, it would be a … Read more
It’s strange to see so many people using shell scripting for this. I was looking for a way to use native makefile syntax, because I’m writing this outside of any target. You can use the wildcard function to check if file exists: ifeq ($(UNAME),Darwin) SHELL := /opt/local/bin/bash OS_X := true else ifneq (,$(wildcard /etc/redhat-release)) OS_RHEL … Read more
If you’ve exported the environment variable: export demoPath=/usr/local/demo you can simply refer to it by name in the makefile (make imports all the environment variables you have set): DEMOPATH = ${demoPath} # Or $(demoPath) if you prefer. If you’ve not exported the environment variable, it is not accessible until you do export it, or unless … Read more
Actually you are right: it runs another instance of make. A possible solution would be: .PHONY : clearscr fresh clean all all : compile executable clean : rm -f *.o $(EXEC) fresh : clean clearscr all clearscr: clear By calling make fresh you get first the clean target, then the clearscreen which runs clear and … Read more