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Need Help w/ Annoying Makefile Errors -- g++: g++ and shell errors -- and Multi-Makefile Design Advice

Answer 1

A:

For a start you can get rid of all the mv commands and use make's built-in variables, e.g.

$(OBJ_DIR)/parameter_manager.o: $(SOURCE_DIR)/parameter_manager.cpp $(SOURCE_DIR)/common.h
    $(CC) $(CFLAGS) -o $@ $<

Paul R 2010-06-29 22:55:00

How does the `$@` and `$<` work... will these drop the objects in my object folder (where my final build is performed)? I'd like to keep them separate...

Jason R. Mick 2010-06-29 22:59:53

@Jason R. Mick: they are Automatic Variables (see the gnu make manual). `$@` expands to the target, and `$<` expands to the first prerequisite.

Beta 2010-06-30 05:46:37

Ahh. Quick question; I work in a lab where most people know much less than coding than me, so maintaining this project may be difficult to say the least. I'm afraid putting nice tricks like that in will worsen that situation. I'm not sure whether I should be trying to write my code/makefiles for readability for novices or for optimal grammar, so to speak. Suggestions??Also does NO ONE have an idea about my original make system errors?????

Jason R. Mick 2010-07-01 21:26:20

@Jason: ideally you want to simplify your makefile, which may make it a little more cryptic but this will hopefully be outweighed by ease of maintenance - look at default rules in the GNU make manual, using the `%` wildcard. You should be able to set up some default rules and then your less enlightened colleagues just have to update the dependencies, which should be pretty easy and doesn't require understanding the more cryptic parts of the makefile.

Paul R 2010-07-01 22:41:10

Thanks. Paul. Still no answers on the above errors, though?? ANYONE?

Jason R. Mick 2010-07-06 21:58:07

@Jason: all I can suggest is that you use a "divide and conquer" approach to debugging your makefile - reduce it down to a minimal makefile that just compiles one source file and get that working, then build it up in stages to the full version.

Paul R 2010-07-07 08:39:46

Answer 2

+1 A:

This fix seems to clear up both of your errors:

molecule_test : molecule_test_prepare_sources molecule_test_prepare_makefiles \
  molecule_test_prepare_data_files
    @cd $(TEST_DIR)/molecule_unit_test && $(MAKE) ./bin/molecule_test

The $(shell ...) command is for invoking a shell outside of a rule. There's no need to use it here, since this is a command in a rule-- it's already happening in a subshell. Also note that this uses $(MAKE) instead of make (the reasons are a little subtle, just think of it as a good habit).

You can do it even more concisely and quietly:

molecule_test : molecule_test_prepare_sources molecule_test_prepare_makefiles \
  molecule_test_prepare_data_files
    @$(MAKE) -s -C $(TEST_DIR)/molecule_unit_test ./bin/molecule_test

As for streamlining, there's a lot you can do. You can reduce the length of your second makefile by about half, and fix what appear to be a number of bugs, and with the first one you can do even better. It depends on how much "magic" you can tolerate. Here's a quick attempt at streamlining your second Makefile (since I don't have your files to test it with I can't promise it'll work without some touchups).

CC=g++
CFLAGS=-c -Wall
SOURCE_DIR:=./source
INCDIRS := -I$(SOURCE_DIR)
OBJ_DIR:=./obj
EXE_DIR:=./bin

VPATH = $(SOURCE_DIR)

$(EXE_DIR)/molecule_test : $(OBJ_DIR)/main.o \
  $(OBJ_DIR)/parameter_manager_lj_molecule.o \
  $(OBJ_DIR)/parameter_manager.o $(OBJ_DIR)/parser.o \
  $(OBJ_DIR)/molecule_manager.o $(OBJ_DIR)/molecule_manager_main.o \
  $(OBJ_DIR)/molecule_reader.o \
  $(OBJ_DIR)/molecule_reader_psf_pdb.o
    @$(CC) $^ -o $@

$(OBJ_DIR)/main.o $(OBJ_DIR)/molecule_reader.o \
  $(OBJ_DIR)/molecule_reader_psf_pdb.o: \
  molecule_manager.h \
  molecule_manager_main.h \
  parameter_manager.h \
  parameter_manager_lj_molecule.h

$(OBJ_DIR)/main.o: main.cpp \
  molecule_reader.h \
  molecule_reader_psf_pdb.h common.h
    $(CC) $(CFLAGS) $(INCDIRS) $< $@

$(OBJ_DIR)/molecule_reader_psf_pdb.o: molecule_reader.h

$(OBJ_DIR)/parameter_manager_lj_molecule.o: parser.h

%.o: %.cpp %.h common.h
    $(CC) $(CFLAGS) $(INCDIRS) $< -o $@

Beta 2010-06-30 00:02:28

I think you need a `-o` before the `$@` in the last line ?

Paul R 2010-06-30 07:05:40

@Paul R: you're right, thank you, fixed. And it probably has a more serious bug or two that will come out in testing.

Beta 2010-06-30 13:05:15

Thank you both!! Will try this out now. :)

Jason R. Mick 2010-07-07 21:49:26

hmm I'm getting the error:`make[1]: *** No rule to make target `main.cpp', needed by `obj/main.o'. Stop.`... when I try to make the second target...

Jason R. Mick 2010-07-07 22:45:00

Okay fixed my previous error by changing the .cpp to .cc in the main.o target... but now I get this error...`obj/main.o: file not recognized: File format not recognized` ... I read that's due to if you have the file extension wrong... but my extension all look right now :O

Jason R. Mick 2010-07-07 22:57:56

hurrah! I just needed to recompile. The stale main.o object was apparently messing me up... But yea your makefile was spot on, as you couldn't have known I would name it *.cc instead of *.cpp.

Jason R. Mick 2010-07-07 23:00:32

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Need Help w/ Annoying Makefile Errors -- g++: g++ and shell errors -- and Multi-Makefile Design Advice

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