I would like a way to take the argument to a call invocation in a Makefile rule and pass that to a builtin function, in this case wildcard.
This doesn't seem to work:
MODULE_OBJS = $(patsubst %.cc, %.o, $(wildcard $(1)/*.cc))
lib%.a: $(call MODULE_OBJS, %)
#echo $# : $^
In this case I would expect make libfoo.a to print a list of .o files corresponding to the .cc files found under foo/, but nothing is printed. The parameter is getting there because if I append $(1) to the end of MODULE_OBJS the value of % gets printed, but it seems to be lost when getting passed into wildcard.
You need to understand that make will execute $(call MODULE_OBJS, %) before it has even begun building the dependency tree, you cannot accomplish this with a pattern rule. You could use eval hackery but there's a case to made against trying to be too clever with make.
Something like the following is easy enough to maintain
MODULE_OBJS = $(patsubst %.cc, %.o, $(wildcard $(1)/*.cc))
libfoo.a: $(call MODULE_OBJS, foo)
lib%.a:
#echo $#: $^
but after wrestling with clever ways of generating library and binary dependencies I prefer simply listing them explicitly.
I got what I wanted with some hacking of the eval rule:
EXCLUDE_MODULES = obj
MODULES = $(filter-out $(EXCLUDE_MODULES), $(patsubst %/, %, $(wildcard */)))
define MODULE_RULE
lib$(MODULE).a: $(patsubst %.cc, obj/%.o, $(wildcard $(MODULE)/*.cc))
#echo $# : $^
endef
$(foreach MODULE, $(MODULES), $(eval $(MODULE_RULE)))
This allows you to call make libfoo.a and get out a list of all the .o's corresponding with the .cc's in that subdirectory.
For those curious, I uploaded a complete example here.
The Metaprogramming Make articles were a useful resource here.
Related
I have a question to this expression:
%.out: %.cpp Makefile
g++ $< -o $# -std=c++0x
What does it mean? I know, that it is defined target for *.o files but what does it mean %.cpp Makefile and $< and $#?
And:
What is differenece between:
all: $(patsubst %.cpp, %.o, $(wildcard *.cpp))
and:
all:
$(patsubst %.cpp, %.o, $(wildcard *.cpp))
The second doesn't works.
For the first part of your question:
%.out: %.cpp Makefile
g++ $< -o $# -std=c++0x
This is a pattern rule, and means: "for all files with a .cpp extension, compile (if needed) a corresponding .out file using the command g++ $< -o $# -std=c++0x
In this line, $< is the prerequisite (the .cpp file) , $# is the name of the target (the .out file). See here.
The rule also adds the makefile itself as a prerequisite, which means that all the files will be rebuild (even if they are already compiled) when you issue a make target command, if you make changes to the makefile.
For the second part of the question, your are mixing two things. A make rule is made of three parts:
target: dependencies
commands
The second one you show cannot work because there is no command. The line just produces a bunch of filenames, that your shell cannot understand.
The first one adds to the list of dependencies all the object files, whose names are deduced from all the .ccp files. But you are missing a command, so nothing should happen (unless you didn't give us the whole rule ?)
Edit: ouch, missed something, this rule actually should work fine, as make will evaluate all the prerequisite targets, thus call the pattern rule described above. I got confused by the fact that this structure is usually written like this:
targetname: $(OUTFILES)
#echo "- Done target $#"
with the variable defined above as:
OUTFILES = $(patsubst %.cpp, %.o, $(wildcard *.cpp))
or even as:
INFILES = $(wildcard *.cpp)
OUTFILES = $(patsubst %.cpp, %.o, $(INFILES))
I suggest you find a good make tutorial, or read the manual, you seem to have lots of concepts to learn...
I am VERY new to makefiles. I have discovered a flaw in a make file that causes files in a list to be copied from a single source file instead of each file in the list.
First, there is a sub model variable SUB_MODEL_LIST that contains 0 1 2 3 separated by white space.
Here is the segment that does the copy:
$(TARGET_BIN_LIST_NEW) : $(TARGET_BIN_LIST)
#echo copying from $< to $#
$(call COPY, $(firstword $(TARGET_BIN_LIST)), $#)
TARGET_BIN_LIST_NEW contains new file names separated by white space and is composed of something like this:
file001.200 file001.201 file001.202 file001.203
and TARGET_BIN_LIST contains the existing file names and is composed of something like this:
file001c.200 file001c.201 file001c.202 file001c.203
The last digit in the file extension is the model number.
As I read this, the makefile runs:
#echo copying from $< to $#
$(call COPY, $(firstword $(TARGET_BIN_LIST)), $#)
four times, however, it always use the first file name in the TARGET_BIN_LIST due to the firstword function. This results in file001.200, file001.201, file001.202, file001.203 being created, but they are all copies of file001c.200 when they should be copies of their respective files in the list. Each file relates to a sub model version of the code.
My thought to solve this was to use the word function. Something like this:
$(TARGET_BIN_LIST_NEW) : $(TARGET_BIN_LIST)
#echo copying from $< to $#
$(call COPY, $(word $(sub), $(TARGET_BIN_LIST)), $#)
where sub is an element of SUB_MODEL_LIST, but I am not sure how that will work. Does the above roll out into 4 separate calls, or can it be looked at as a loop that can have an increment value for sub??
I also thought about using a foreach loop:
$(foreach sub,$(SUB_MODEL_LIST),$(call COPY, $(word $(sub), $(TARGET_BIN_LIST)), $(word $(sub), $(TARGET_BIN_LIST_NEW)))
But I get the error:
*** first argument to `word' function must be greater than 0. Stop.
Ok, so I tried:
$(foreach sub,$(SUB_MODEL_LIST),$(call COPY, $(word $(sub)+1, $(TARGET_BIN_LIST)), $(word $(sub)+1, $(TARGET_BIN_LIST_NEW)))
But then I got the error:
*** non-numeric first argument to `word' function. Stop.
Now I'm stuck. I would like to keep the existing implementation in tact at much as possible, but can adopt a loop method if needed.
Thanks for the help!
You have to step back. You're misunderstanding how this works. In make an explicit rule with multiple targets is EXACTLY THE SAME as writing the same rule multiple times, once for each target. So this:
$(TARGET_BIN_LIST_NEW) : $(TARGET_BIN_LIST)
#echo copying from $< to $#
$(call COPY, $(firstword $(TARGET_BIN_LIST)), $#)
If TARGET_BIN_LIST_NEW is file001.200 file001.201 file001.202 file001.203 and TARGET_BIN_LIST is file001c.200 file001c.201 file001c.202 file001c.203, is identical to writing this:
file001.200 : file001c.200 file001c.201 file001c.202 file001c.203
...
file001.201 : file001c.200 file001c.201 file001c.202 file001c.203
...
file001.202 : file001c.200 file001c.201 file001c.202 file001c.203
...
file001.203 : file001c.200 file001c.201 file001c.202 file001c.203
...
So you can clearly see that when each rule is run, the value of $< and $(firstword $(TARGET_BIN_LIST)) will be the same thing (file001c.200).
Is it really the case that whenever ANY of the fileXXXc.YYY files change, you want to rebuild ALL the fileXXX.YYY files? That's what your rule does, but based on the recipe it doesn't seem like that's what you want.
Make is mostly about writing one rule to build one target from zero or more prerequisites. If you use a pattern rule you can do this pretty easily:
all: $(TARGET_BIN_LIST_NEW)
file001.% : file001c.%
#echo copying from $< to $#
$(call COPY,$<,$#)
If your filenames may have a more complex naming convention then you'll need something more complicated.
ETA:
Since your naming convention doesn't fit into make's pattern rule capabilities you'll have to do something fancier. You can use eval to generate the rules, like this:
all: $(TARGET_BIN_LIST_NEW)
define TARGET_BIN_COPY
$(1) : $(basename $(1))c$(suffix $(1))
#echo copying from $$< to $$#
$$(call COPY,$$<,$$#)
endef
$(foreach T,$(TARGET_BIN_LIST_NEW),$(eval $(call TARGET_BIN_COPY,$T)))
# uncomment this for debugging
#$(foreach T,$(TARGET_BIN_LIST_NEW),$(info $(call TARGET_BIN_COPY,$T)))
First off, thank you to MadScientist for your help in clarifying how this works.
This implementation worked for me:
$(TARGET_BIN_LIST_NEW) : $(TARGET_BIN_LIST)
#echo copying from $(filter %$(suffix $#), $(TARGET_BIN_LIST)) to $#
$(call COPY, $(filter %$(suffix $#), $(TARGET_BIN_LIST)), $#)
I have the following rule:
EXECS = $(sort $(patsubst %.cpp,%$(EXESUFFIX), $(patsubst %.c,%$(EXESUFFIX), $(filter-out $(IGNORESRCS), $(EXECSRCS)))))
SRCS = $(sort $(filter-out $(EXECSRCS), $(filter-out $(IGNORESRCS), $(wildcard *.c) $(wildcard *.cpp) $(foreach DIR,$(SUBDIRS),$(wildcard $(DIR)/*.cpp) $(wildcard $(DIR)/*.c) ) )))
#OBJS = $(addprefix $(OBJDIR), $(patsubst %.cpp,%$(OBJSUFFIX), $(patsubst %.c,%$(OBJSUFFIX), $(SRCS))))
OBJS = $(patsubst %.cpp,%$(OBJSUFFIX), $(patsubst %.c,%$(OBJSUFFIX), $(SRCS)))
RESOURCE_SRCS= $(sort $(filter-out $(IGNORESRCS), $(wildcard *.rc) $(foreach DIR,$(SUBDIRS),$(wildcard $(DIR)/*.rc) ) ))
RESOURCES = $(patsubst %.rc,%$(OBJSUFFIX), $(RESOURCE_SRCS))
%$(EXESUFFIX) : %.cpp $(LIBS) $(RESOURCES)
$(CXX) $(DEFINES) $(CFLAGS) $(INCLUDES) $(LIBPATH) -o $(BINDIR)/$* $< $(RESOURCES) $(LIBINCLUDES)
The problem is that $(RESOURCES) doesnt exist for all platforms. The %$(EXESUFFIX) : %.cpp rule doesnt run, instead it tries to run g++ exec.cpp -o exec which as far as I can tell isnt a rule that I declared anywhere.
How do I get the rule to still build despite the fact that it is empty (and build the resources if it is not empty)?
If the variable is empty it has no effect on the rule. It should just work as written. What is the actual error you're seeing?
ETA:
Your question is very unclear in what, exactly, you mean by $(RESOURCES) doesn't exist. My answer was assuming you meant that the variable was empty. But given your comment below about how the makefile behaves, I now suspect what you mean is that the variable is still set to a list of files, but that those files are not present.
Because they're not there, and make doesn't know how to build them, make decides that this pattern rule cannot be used at all and it chooses a different rule.
If you want these files to only have any impact if they exist, then you can use the $(wildcard ...) function to expand only to those files that exist:
%$(EXESUFFIX) : %.cpp $(LIBS) $(wildcard $(RESOURCES))
$(CXX) ...
One critical point here: the contents of $(RESOURCES) MUST be source files. They cannot be derived files (files that are supposed to be created by make). If they are derived, the situation is far more complex.
I'm having trouble getting path substitution working correctly. I have a bunch of source files in SOURCES:
#echo $(SOURCES)
foo.c bar.cpp bah.cxx
And I want a list of object files:
# Imaginary only because nothing works
#echo $(OBJECTS)
foo.o bar.o bah.o
I'm trying to build the list of OBJECTS with patsubst. First, this produces a list of source files and object files. Besides being wrong, it causes a duplicate of _main which fails a link.
OBJECTS = $(patsubst %.c, %.o, ${SOURCES}) $(patsubst %.cc, %.o, ${SOURCES}) \
$(patsubst %.cpp, %.o, ${SOURCES}) $(patsubst %.cxx, %.o, ${SOURCES})
Second, this performs no substitutions. Not only is it wrong, I get back the original list in SOURCES.
OBJECTS = $(patsubst %.c %.cc %.cpp %.cxx, %.o, ${SOURCES})
Third, this produces the original list of source files:
OBJECTS = $(patsubst %.*, %.o, ${SOURCES})
I also tried using the following, which seems to multiply the files like rabbits:
OBJECTS = $(SOURCES:.c=.o) $(SOURCES:.cc=.o) \
$(SOURCES:.cpp=.o) $(SOURCES:.cxx=.o)
How does one perform a simple substitution of extensions when using a portable make?
Tom's answer is correct. Etan's will work too. A shorter solution would be:
$(addsuffix .o,$(basename $(SOURCES))
If you have a filter-like function you can use that. Otherwise you can do it in stages:
SOURCES := foo.c bar.cpp bah.cxx
O := $(SOURCES)
$(info $(O))
O := $(patsubst %.c,%.o,$(O))
$(info $(O))
O := $(patsubst %.cpp,%.o,$(O))
$(info $(O))
O := $(patsubst %.cxx,%.o,$(O))
$(info $(O))
The problem with your first (and third since that is effectively identical) attempt is that patsubst leaves untouched any words in the input that do not match the pattern. So when you built OBJECTS up from multiple calls to patsubst you were duplicating (in each piece) all the SOURCSE entries that didn't match that pattern.
The problem with the second is that patsubst doesn't take multiple patterns so nothing matches that erroneous pattern and so you get SOURCES back entirely unmodified.
First, I don't think patsubst is portable. It is a GNU make feature.
I think one answer to your question is nested subsitutions, like:
$(patsubst %c,%.o,$(patsubst %.cc,%.o,$(patsubst .....)))
I have a set of .cpp files that I want to compile. These .cpp files are in a hierarchical directory structure. I want the corresponding .o files to all end up in one build folder.
Here's how I get GNU make to enumerate the files:
SRCS = \
$(wildcard $(CODE)/**/*.cpp) \
$(wildcard $(CODE)/AlgebraLibraries/**/*.cpp) \
$(wildcard $(CODE)/Calculator/Environments/**/*.cpp)
BARE_SRCS = $(notdir $(SRCS))
BARE_OBJS = $(BARE_SRCS:.cpp=.o)
OBJS = $(addprefix $(BUILD)/, $(BARE_OBJS))
Having done this, I have no idea how to create the rules that will create the .o files from the .cpp files. Intuitively, what I want to do is the following pseudocode:
for i=0, N do # <-- a for-loop!
$(OBJS)[i]: $(SRCS)[i] # <-- the rule!
$(CPP) -c $(SRCS)[i] -o $(OBJS)[i] # <-- the recipe
end
Of course, this is not valid GNU make code, but I trust you understand what it is here that I'm trying to do. The following will not work.
%.o: %.cpp
$(CPP) -c $< -o $#
This doesn't work, because GNU make is matching up the % signs, assuming that the .o files live along-side the .cpp files.
The alternative to all of this, which I know will work, but will be extremely tedious, is to enumerate all of the rules by-hand as explicit rules. There has to be a better way!
I've been researching GNU make's ability to generate rules, but there appears to be no way to do it without the built-in logic. It would be really nice if I could utilize some flow-control statements to generate the rules that I want to make. Is this asking too much of GNU-make?
In any case, is there a way to do what it is I'm trying to do with GNU make? If so, how?
This looks like a job for... several advanced Make tricks:
all: $(OBJS)
define ruletemp
$(patsubst %.cpp, $(BUILD)/%.o, $(notdir $(1))): $(1)
$$(CPP) -c $$< -o $$#
endef
$(foreach src,$(SRCS),$(eval $(call ruletemp, $(src))))
If $(BUILD) is constant, you can always just do:
$(BUILD)/%.o: %.cpp
$(CPP) -c $< -o $#