string comparison in makefile - makefile

how do we compare strings in makefile?
in makefile
MAKECMDGOALS ?= debug
DBGDIR = build/debug
RLSDIR = build/release
ifeq ($(MAKECMDGOALS),"debug")
O = $(DBGDIR)
else
O = $(RLSDIR)
endif
I tried following comparisons:
($(MAKECMDGOALS),"debug")
($(MAKECMDGOALS),debug)
($(MAKECMDGOALS),'debug')
($(MAKECMDGOALS), ' debug')
also
ifeq "$(strip $(filter debug,$(MAKECMDGOALS)))" "debug"
but everytime it enter else block and does release build.
Where am i going wrong?

For sure you should not have any quotation marks. The following works for me:
$ cat Makefile
MAKECMDGOALS ?= debug
DBGDIR = build/debug
RLSDIR = build/release
ifeq ($(MAKECMDGOALS),debug)
O = $(DBGDIR)
else
O = $(RLSDIR)
endif
all:
%:
#echo $(O)
$ make
build/debug
$ make foo
build/release
But I would advise against checking it this way, as $(MAKECMDGOALS) may have more than one target and the test will fail:
$ make debug
build/debug
$ make debug foo
build/release
build/release
If you still wish to check this variable, it would be better to check if an interesting target shows among others, i.e.:
$ cat Makefile
MAKECMDGOALS ?= debug
DBGDIR = build/debug
RLSDIR = build/release
ifeq ($(findstring debug,$(MAKECMDGOALS)),debug)
O = $(DBGDIR)
else
O = $(RLSDIR)
endif
all:
%:
#echo $(O)
$ make debug
build/debug
$ make debug foo
build/debug
build/debug

Related

Makefile wildcard for makefile variables, to define generic rules

Background, I suspect XY problem
I have simpler C modules in a directory. I want to write unit tests for these in a sub-directory test/. These unit tests are no more than C programs linking to the module under test, one directory above. I want a Makefile that defines several build targets and lets me build and run the test executables in one step, or separately.
My attempted solution
I've attempted the following:
CC = gcc
CFLAGS = -ggdb -Wall -Wextra -Werror -O3 -std=c99
PARAM_LIST_TARGET = parameter_list_test
PARAM_LIST_SOURCE_FILES = \
../parameter_list.c \
parameter_list_test.c
PARAM_LIST_OBJECT_FILES := $(addsuffix .o,$(basename $(PARAM_LIST_SOURCE_FILES)))
TARGETS = $(PARAM_LIST_TARGET)
all: $(TARGETS)
$(%_TARGET): $(%_OBJECT_FILES)
$(CC) $(CFLAGS) $^ -o $#
.c.o:
$(CC) -c $< -o $# $(CFLAGS)
clean:
$(RM) *.o $(TARGETS)
test: all
#for t in $(TARGETS) ; do ./$$t ; done
This doesn't work, and it's because of the $(%_TARGET): row. Not surprising, I didn't expect it to work, but I hope this illustrates what I'm trying to achieve.
I want to create more chunks of the form _TARGET, _SOURCE_FILES, and _OBJECT_FILES, to test other modules besides PARAM_LIST, for example:
PARAM_LIST_TARGET = parameter_list_test
PARAM_LIST_SOURCE_FILES = \
../parameter_list.c \
parameter_list_test.c
PARAM_LIST_OBJECT_FILES := $(addsuffix .o,$(basename $(PARAM_LIST_SOURCE_FILES)))
OTHER_MODULE_TARGET = other_module_test
OTHER_MODULE_SOURCE_FILES = \
../other_module.c \
other_module_test.c
OTHER_MODULE_OBJECT_FILES := $(addsuffix .o,$(basename $(OTHER_MODULE_SOURCE_FILES)))
I understand that % works on filenames, so attempting to use it on variables fails:
$(%_TARGET): $(%_OBJECT_FILES)
$(CC) $(CFLAGS) $^ -o $#
How can I write a rule that matches the Makefile variables _TARGET to their associated _OBJECT_FILES, without creating one per test target?
Or more importantly, how should I do it totally differently?
Edit: I've seen this, however it seems it's only working with a single source file per executable.
You can always access make variables by constructing their names:
MY_VAR := "my var"
HIS_VAR := "his var"
HER_VAR := "her var"
CATS_VAR := "cats var"
DOGS_VAR := "dogs var"
ALL_PERSONS := MY HIS HER CATS DOGS
ALL_VARS := $(foreach p,$(ALL_PERSONS),$($(p)_VAR))
$(info $(ALL_VARS))
Output:
$ make
"my var" "his var" "her var" "cats var" "dogs var"
Defining the dependencies separately seems to work, thanks to this answer:
TARGETS = $(PARAM_LIST_TARGET) $(OTHER_MODULE_TARGET)
all: $(TARGETS)
$(PARAM_LIST_TARGET): $(PARAM_LIST_OBJECT_FILES)
$(OTHER_MODULE_TARGET): $(OTHER_MODULE_OBJECT_FILES)
$(TARGETS):
$(CC) $(CFLAGS) $^ -o $#
This eliminates the need for a duplicate rule (one per target). Still, the definition of dependencies for each target looks like duplicates, a pattern match for these would be nice.
More than that, the OBJECT_FILES variable becomes unnecessary. This works:
PARAM_LIST_TARGET = parameter_list_test
PARAM_LIST_SOURCE_FILES = \
../parameter_list.c \
parameter_list_test.c
$(PARAM_LIST_TARGET): $(addsuffix .o,$(basename $(PARAM_LIST_SOURCE_FILES))) # The dependencies directly
It would still feel nice to have this last row as one rule for all targets. Something like "for all variables ending with TARGET, build a dependency to the content of the variable with the same name, but ending with SOURCE_FILES instead".

Variables in non-recursive Makefiles

I'm using GNU Make and attempting to design Makefiles using non-recursive approach. The issue I have - there doesn't seem to be a way to limit the scope of variables in different Makefiles.
For example, if I have two Makefiles for modules libA and libB
libA Makefile.inc:
src_dir := libA/src
inc_dir := libA/inc
libB Makefile.inc:
src_dir := libB/src
inc_dir := libB/inc
Then when I include the above Makefiles into a master Makefile
include libA/Makefile.inc
include libB/Makefile.inc
Values in variables src_dir and inc_dir are overwritten by the very last Makefile that was included. OK this is probably expected since variables are global in scope here, and this messes up build commands that use those variables, i.e. build command for libA finds variable values for libB.
A way around it is to create unique variables for each Makefile
libA Makefile.inc:
src_dir_libA := libA/src
inc_dir_libA := libA/inc
libB Makefile.inc:
src_dir_libB := libB/src
inc_dir_libB := libB/inc
This solves the issue, but it's a bit awkward to use, since each variable has to be renamed. Does anyone know if there is a better way to solve this, e.g. if GNU Make has some notion of scope or namespace? I've looked at documentation, but can't seem to find anything of that sort. There are target-specific variables, but they appear to have nasty side-effects.
OK, just to be very specific, below is an example Makefile
dep_all :=
all:
# Begin Makefile.inc for project1
# ------------------------------------------------------------------------------
$(foreach var,$(filter local_%,$(.VARIABLES)),$(eval $(var) := ))
local_src_dir := project1/src
local_obj_dir := project1/obj
local_src := $(local_src_dir)/fileA.c $(local_src_dir)/fileB.c
local_obj := $(patsubst $(local_src_dir)/%.c,$(local_obj_dir)/%.o,$(local_src))
dep_all += $(local_src)
dep_all += $(local_obj)
$(info local_obj="$(local_obj)")
$(local_obj): $(local_obj_dir)/%.o: $(local_src_dir)/%.c
gcc -L$(local_obj_dir) -c -o $# $<
# ------------------------------------------------------------------------------
# End Makefile.inc for project1
# Begin Makefile.inc for project2
# ------------------------------------------------------------------------------
$(foreach var,$(filter local_%,$(.VARIABLES)),$(eval $(var) := ))
local_src_dir := project2/src
local_obj_dir := project2/obj
local_src := $(local_src_dir)/fileX.c $(local_src_dir)/fileY.c
local_obj := $(patsubst $(local_src_dir)/%.c,$(local_obj_dir)/%.o,$(local_src))
dep_all += $(local_src)
dep_all += $(local_obj)
$(info local_obj="$(local_obj)")
$(local_obj): $(local_obj_dir)/%.o: $(local_src_dir)/%.c
gcc -L$(local_obj_dir) -c -o $# $<
# ------------------------------------------------------------------------------
# End Makefile.inc for project2
$(info dep_all="$(dep_all)")
.PHONY: all
all: $(dep_all)
.PHONY: clean
clean:
rm -f project1/obj/* project2/obj/*
If I run it then the -L<object_path> option passed to gcc contains value from the last included Makefile, i.e. when building project1, it runs gcc with -Lproject2/obj, which is not the right object path for this project. This is the problem I'm trying to solve.
mkdir -p project1/{src,obj} project2/{src,obj}
touch project1/src/{fileA.c,fileB.c} project2/src/{fileX.c,fileY.c}
$ make
local_obj="project1/obj/fileA.o project1/obj/fileB.o"
local_obj="project2/obj/fileX.o project2/obj/fileY.o"
dep_all=" project1/src/fileA.c project1/src/fileB.c project1/obj/fileA.o project1/obj/fileB.o project2/src/fileX.c project2/src/fileY.c project2/obj/fileX.o project2/obj/fileY.o"
gcc -Lproject2/obj -c -o project1/obj/fileA.o project1/src/fileA.c
gcc -Lproject2/obj -c -o project1/obj/fileB.o project1/src/fileB.c
gcc -Lproject2/obj -c -o project2/obj/fileX.o project2/src/fileX.c
gcc -Lproject2/obj -c -o project2/obj/fileY.o project2/src/fileY.c
The solution is to name all your variables local to a specific file with some prefix.
For example, I use this_ prefix.
Then, in the beginning of each submakefile those variales which have this_ prefix can be cleared as follows:
$(foreach var,$(filter this_%,$(.VARIABLES)),$(eval $(var) := ))
PS. I use this approach in my implementation of non-recursive makefiles, clearing the variables described in the WIKI here: https://github.com/cppfw/prorab
I think I've just figured out a solution. I was reading "The GNU Make Book" and it states a side effect of target specific variables
Target-specific variables apply not just to a target, but also to all
that target’s prerequisites, as well as all their prerequisites, and
so on. A target-specific variable’s scope is the entire tree of
targets, starting from the target for which the variable was defined.
This is not the behaviour I want, however starting with GNU Make 3.82 there is support for private target specific variables
A target-specific variable is normally defined for a target and all
its prerequisites. But if the target-specific variable is prefixed
with the keyword private, it is defined only for that target, not its
prerequisites.
So the following Makefile seems to work correctly for those private variables
dep_all :=
all:
# Begin Makefile.inc for project1
# ------------------------------------------------------------------------------
inc_dir := project1/inc
src_dir := project1/src
obj_dir := project1/obj
src := $(src_dir)/fileA.c $(src_dir)/fileB.c
obj := $(patsubst $(src_dir)/%.c,$(obj_dir)/%.o,$(src))
# These flags will be overwritten by another Makefile
CFLAGS := -I$(inc_dir)
# These flags will be private and not be overwritten by another Makefile
CFLAGS_priv := -I$(inc_dir) -L$(obj_dir)
dep_all += $(src)
dep_all += $(obj)
# Private target specific variables
$(obj): private CFLAGS_priv:=$(CFLAGS_priv)
$(obj): $(obj_dir)/%.o: $(src_dir)/%.c
gcc $(CFLAGS) $(CFLAGS_priv) -c -o $# $<
# ------------------------------------------------------------------------------
# End Makefile.inc for project1
# Begin Makefile.inc for project2
# ------------------------------------------------------------------------------
inc_dir := project2/inc
src_dir := project2/src
obj_dir := project2/obj
src := $(src_dir)/fileX.c $(src_dir)/fileY.c
obj := $(patsubst $(src_dir)/%.c,$(obj_dir)/%.o,$(src))
# These flags will be overwritten by another Makefile
CFLAGS := -I$(inc_dir)
# These flags will be private and not be overwritten by another Makefile
CFLAGS_priv := -I$(inc_dir) -L$(obj_dir)
dep_all += $(src)
dep_all += $(obj)
# Private target specific variables
$(obj): private CFLAGS_priv:=$(CFLAGS_priv)
$(obj): $(obj_dir)/%.o: $(src_dir)/%.c
gcc $(CFLAGS) $(CFLAGS_priv) -c -o $# $<
# ------------------------------------------------------------------------------
# End Makefile.inc for project2
.PHONY: all
all: $(dep_all)
.PHONY: clean
clean:
rm -f project1/obj/* project2/obj/*
The output is what I wanted, since now for each project I can define private CFLAGS_priv variable that sets -I<dir>, -L<dir> paths and it won't be overwritten by other Makefiles.
$ make
gcc -Iproject2/inc -Iproject1/inc -Lproject1/obj -c -o project1/obj/fileA.o project1/src/fileA.c
gcc -Iproject2/inc -Iproject1/inc -Lproject1/obj -c -o project1/obj/fileB.o project1/src/fileB.c
gcc -Iproject2/inc -Iproject2/inc -Lproject2/obj -c -o project2/obj/fileX.o project2/src/fileX.c
gcc -Iproject2/inc -Iproject2/inc -Lproject2/obj -c -o project2/obj/fileY.o project2/src/fileY.c
I'm hoping this will resolve all issues I had and I don't have to use recursive make with it's various associated pitfalls.

Makefile set variable in target

I have a makefile where a variable $DEBUG decides whether to build for deployment or debugging. There is one main Makefile, and multiple platform-specific makefiles that get included. I want the variable $DEBUG to be set to 1 automatically when the target test is built.
The main makefile:
DEBUG := 0
test : override DEBUG := 1
DIST_DIR := dist/
ifeq ($(DEBUG), 1)
BUILD_DIR := build/debug
else
BUILD_DIR := build/deploy
endif
# detect operating system
ifeq ($(OS), Windows_NT)
UNAME := Windows
else
UNAME := $(shell uname -s)
endif
# include platform-specific Makefile
export
ifeq ($(UNAME), Darwin)
include Makefile.darwin
endif
ifeq ($(UNAME), Linux)
include Makefile.linux
endif
And the platform-specific Makefile.linux:
...
CXX := clang++-3.8
CXXFLAGS := -std=c++14 -fPIC -I./external/include -fcolor-diagnostics
LDFLAGS :=
LDLIBS := -lpthread -lm
ifeq ($(DEBUG), 1)
CXXFLAGS += -g
else
CXXFLAGS += -O3 -DNDEBUG
endif
...
all : $(TARGET)
test : $(TEST_TARGET)
$(TEST_TARGET)
So there are two rules for test: One in the main makefile sets the target-specific variable $DEBUG, and the one in Makefile.linux builds the test. The variables used for building ($CXXFLAGS, $BUILDDIR, and others) are set before the rules, and use conditionals.
Everything in the makefiles is working correctly, however calling make test does not alter the variable $DEBUG: both $CXXFLAGS and $BUILDDIR still get set to the values they would have for a deployment built.
Is there a way to first set $DEBUG := 1 in Makefile when the target is test, and then normally proceed?
Or is there a special variable that contains the target name, for example
ifeq ($(MAKEFILE_TARGET), test)
...
endif
test : override DEBUG := 1 doesn't work because it declares a target-specific variable that is only visible within that recipe.
There does exist a variable containing the target names that were specified at the command line: MAKECMDGOALS. Note that it doesn't include the default target if it wasn't explicitly specified at the command line.
Example makefile:
DEBUG := $(filter test,$(MAKECMDGOALS))
all:
#echo all : $(MAKECMDGOALS) : $(DEBUG) : $(if $(DEBUG),1,0)
test:
#echo test : $(MAKECMDGOALS) : $(DEBUG) : $(if $(DEBUG),1,0)
Usage:
$ make
all : : : 0
$ make all
all : all : : 0
$ make test
test : test : test : 1
$ make all test
all : all test : test : 1
test : all test : test : 1
One simple option is to have your test target recursively invoke make with DEBUG=1. That works with included makefiles as well. Example:
DEBUG := 0
test:
make DEBUG=1
DIST_DIR := dist/
...

Makefile - How to call other makefiles with dependencies

Hey, I have a simple "master" Makefile who simply calls other makefiles. I'm trying to do the following in order to build components in the right order:
LIB_A = folder_a
LIB_B = folder_b
LIB_C = folder_c
MY_TARGETS = $(LIB_A) $(LIB_B) $(LIB_C)
.PHONY: $(LIB_A)
$(LIB_A):
#$(MAKE) -C $#;
.PHONY: $(LIB_B)
$(LIB_B):
#$(MAKE) -C $#;
.PHONY: $(LIB_C)
$(LIB_C): $(LIB_A) $(LIB_B)
#$(MAKE) -C $#;
.PHONY: all
all: $(MY_TARGETS)
However, when I make, only LIB_A gets built.
(I don't even get a folder_b up-to-date message or whatever).
Any hint ?
You need to make all the default. You can do this in either of these ways:
move it to be the first target in the file
Add .DEFAULT_GOAL := all
Alternatively, you could run make all instead of just make.
Neil Butterworth solved the problem, but you can also make this makefile a little more concise:
LIB_A = folder_a
LIB_B = folder_b
LIB_C = folder_c
MY_TARGETS = $(LIB_A) $(LIB_B) $(LIB_C)
.PHONY: all $(MY_TARGETS)
all: $(MY_TARGETS)
$(MY_TARGETS):
#$(MAKE) -C $#;
$(LIB_C): $(LIB_A) $(LIB_B)

Problem creating gnu makefile "function"

I have a big chunk of my makefile (~50 lines) that needs to be copy-pasted 5 times for different case (the different libraries used). Is it possible to create a function in a makefile and just call that function instead of copy-pasting?
This is an example of what I've tried. Basically this tries to find the right path for an installed library.
define Flags_template
$(1)_include_home := $(HOME)/usr/include
$(1)_include_home_name := $(HOME)/usr/include/$(1)
ifneq ($$(wildcard $($(1)_include_home)/$(2)),)
$(1)_Include := $$($(1)_include_home)
else
ifneq ($$(wildcard $($(1)_include_home_name)/$(2)),)
$(1)_Include := $$($(1)_include_home_name)
endif
endif
CFLAGS += -I$$($(1)_Include)
endef
$(eval $(call Flags_template,stdcout,StdCout.hpp))
.PHONY: test
test:
# stdcout_include_home_name = $(stdcout_include_home_name)
# stdcout_Include = $(stdcout_Include)
# CFLAGS: $(CFLAGS)
Typing "make", I get this output:
# stdcout_include_home_name = /home/nicolas/usr/include/stdcout
# stdcout_Include =
# CFLAGS: -I
It's so close. But note the last "-I", I always get dupplicates, one fully expended, one empty...
I don't understant what needs to be eval'ed, escaped with two $, etc.
How can I achieve this?
Thank you very much.
Does §8.8 of the GNU Make (3.82) manual help?
[...] Although it might seem overly complex to use eval in this example,
rather than just writing out the rules, consider two things: first, the template definition (in
PROGRAM_template) could need to be much more complex than it is here; and second, you
might put the complex, “generic” part of this example into another makefile, then include
it in all the individual makefiles. Now your individual makefiles are quite straightforward.
PROGRAMS = server client
server_OBJS = server.o server_priv.o server_access.o
server_LIBS = priv protocol
client_OBJS = client.o client_api.o client_mem.o
client_LIBS = protocol
# Everything after this is generic
.PHONY: all
all: $(PROGRAMS)
define PROGRAM_template =
$(1): $$($(1)_OBJS) $$($(1)_LIBS:%=-l%)
ALL_OBJS += $$($(1)_OBJS)
endef
$(foreach prog,$(PROGRAMS),$(eval $(call PROGRAM_template,$(prog))))
$(PROGRAMS):
$(LINK.o) $^ $(LDLIBS) -o $#
clean:
rm -f $(ALL_OBJS) $(PROGRAMS)
This Works (For Me)
This is the output from the GNU makefile just below:
stdcout_include_home = /work4/jleffler/usr/include
stdcout_include_home_name = /work4/jleffler/usr/include/stdcout
stdcout_Include = /work4/jleffler/usr/include
CFLAGS: -I/work4/jleffler/include -I/work4/jleffler/usr/include
GNU Makefile
CFLAGS = -I${HOME}/include
define Flags_template
$(1)_include_home := $(HOME)/usr/include
$(1)_include_home_name := $(HOME)/usr/include/$(1)
ifneq ($$(wildcard $$($(1)_include_home)/$(2)),)
$(1)_Include := $$($(1)_include_home)
else
ifneq ($$(wildcard $$($(1)_include_home_name)/$(2)),)
$(1)_Include := $$($(1)_include_home_name)
else
$(1)_Include := Neither $$($(1)_include_home) nor $$($(1)_include_home_name) contains $2
endif
endif
CFLAGS += -I$$($(1)_Include)
endef
$(eval $(call Flags_template,stdcout,StdCout.hpp))
.PHONY: test
test:
#echo stdcout_include_home = $(stdcout_include_home)
#echo stdcout_include_home_name = $(stdcout_include_home_name)
#echo stdcout_Include = $(stdcout_Include)
#echo CFLAGS: $(CFLAGS)
The difference is in the wildcard invocations:
ifneq ($$(wildcard $($(1)_include_home)/$(2)),) # Fails
ifneq ($$(wildcard $$($(1)_include_home)/$(2)),) # Works
I have half an intuition about when double-dollars and when single-dollars are needed; I am not sure I can articulate the decision, though.

Resources