undefined reference to `main' with makefile on linux, with boost and mpi - c++

Question

I am not very familiar with make; i've always used and modified this highly ancient makefile I inherited from another project, modifying it as necessary. Up until now, it has functioned perfectly, compiling together projects with 20-50 files, even within sub-directories, determining and building all the dependencies properly.
Today I am running a very simple test code to determine if BOOST.MPI will work on a cluster I recently got access to. I am trying to compile a 1-file test case to make sure that the library works. This is also my first time building and linking to boost on this system.
I have boost installed in my user directory: ~/boost, and I've run the appropriate bjam to ensure that BOOST.MPI is present. I don't believe my problem lies there. As you'll see in a moment, however, I had to include -lboost_mpi and -lboost_serialization to get as far as I did.
The makefile seems to compile, and assemble just fine producing the intermediary .a file. It hangs up on the linking step with a surprising error:
Creating dependency for "boosttest.cpp"
Compiling "boosttest.cpp"
Assembling ag...
ar: creating ./libag.a
Linking bt1...
/usr/lib/gcc/x86_64-redhat-linux/4.4.5/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: ld returned 1 exit status
make: *** [bt1] Error 1
The only source code I've written (copy/pasted right out of the Boost.MPI implementation page):
boosttest.cpp:
#include <boost/mpi/environment.hpp>
#include <boost/mpi/communicator.hpp>
#include <iostream>
int main(int argc, char* argv[])
{
boost::mpi::environment env(argc, argv);
boost::mpi::communicator world;
std::cout << "I am process " << world.rank() << " of " << world.size()<< "." << std::endl;
return 0;
}
Now for the part where I get lost. This is the makefile I've modified. I mostly understand what parts of it are doing, and it is the only makefile I've ever seen (although as mentioned I'm not very experienced with them) to produce .d files containing a list of all dependent libraries.
Makefile:
PROJECT = boosttest
# The names of the sub-projects that the executable depends on. These names are used later on to define targets, location, libraries, etc.
DEPS =
# The names of the sub-projects that the test executable depends on.
TEST_DEPS =
EXE_DEPS =
LOCAL_O_FILES = boosttest.o
LOCAL_TEST_O_FILES =
LOCAL_LIB_NAME = ag
LOCAL_LIB_DIR = .
LOCAL_TEST_LIB_NAME =
LOCAL_TEST_LIB_DIR =
LOCAL_INCLUDE_ROOT = .
EXE_NAME = BT
MPIC_DIR = /usr/local/mvapich2-1.6-gcc/
#these assume our local path and bin are set up properly since I don't know where the compilers are
CC = $(MPIC_DIR)/bin/mpicc
CCC = $(MPIC_DIR)/bin/mpicxx
F77 = $(MPIC_DIR)/bin/mpif77
CLINKER = $(MPIC_DIR)/bin/mpicc
CCLINKER = $(MPIC_DIR)/bin/mpicxx
FLINKER = $(MPIC_DIR)/bin/mpif90
F90 = $(MPIC_DIR)/bin/mpif90
F90LINKER = $(MPIC_DIR)/bin/mpif90
MAKE = make --no-print-directory
SHELL = /bin/sh
#PROF = -ggdb -O2
PROF = -O2
ADDITIONAL_LIBS = -lboost_mpi -lboost_serialization
SED = $(shell which sed)
GREP = $(shell which grep)
# Warnings will depend on the GCC version -- if it's 4, have "-Wdeclaration-after-statement -Wunused-value -Wunused-variable"
#GCC_MAJOR_VERSION = $(shell $(CCC) --version | $(GREP) "\(egcs\|gcc\)" | $(SED) "s/[^0-9]*\([0-9]\).*/\1/")
#WARNINGS = -Wno-import $(shell if test $(GCC_MAJOR_VERSION) -eq 4; then echo -Wunused-value -Wunused-variable; fi)
#GCC_INSTALL_DIR = /turing/software-linux/mpich-eth
GCC_INSTALL_DIR = $(MPIC_DIR)
GCC_INCLUDE_DIR = $(GCC_INSTALL_DIR)/include/
GCC_LIB_DIR = $(GCC_INSTALL_DIR)/lib/
BOOST_DIR = ~/boost
BOOST_LIB_DIR = ~/boost/stage/lib
# Expand SRCDIR so that it turns into "-I <srcdir>" for each listed directory
INCLUDE_DIRS = -I $(OBJC_ROOT)/include $(foreach dep, $(UNIQUE_DEPS), -I$($(dep)_INCLUDE_ROOT)) -I $(LOCAL_INCLUDE_ROOT) -I $(BOOST_DIR) -I $(GCC_INCLUDE_DIR)
#C_FLAGS = -DROM $(PROF) $(WARNINGS) $(INCLUDE_DIRS)
C_FLAGS = -DROM $(PROF) $(INCLUDE_DIRS)
L_FLAGS = $(foreach dir, $(OBJC_ROOT) $(DEP_LIB_DIRS), -L$(dir)) -L $(BOOST_LIB_DIR) -L $(GCC_LIB_DIR) $(PROF) $(ADDITIONAL_LIBS)
TEST_L_FLAGS = $(foreach dir, $(OBJC_ROOT) $(TEST_DEP_LIB_DIRS), -L$(dir)) -L/usr/lib -Xlinker --whole-archive $(TEST_REQUIRED_LIBS) -Xlinker --no-whole-archive
REQUIRED_LIBS = $(foreach dep, $(DEPS) LOCAL, $(if $($(dep)_LIB_NAME), -l$($(dep)_LIB_NAME)))
TEST_REQUIRED_LIBS = $(foreach dep, $(TEST_DEPS) LOCAL LOCAL_TEST, $(if $($(dep)_LIB_NAME), -l$($(dep)_LIB_NAME)))
.SUFFIXES:
.SUFFIXES: .d .cc .cpp .c .o
ASSEMBLE_TARGETS = $(foreach dep,$(DEPS),$(dep)_LIB_NAME)
ASSEMBLE_TEST_TARGETS = $(foreach dep,$(TEST_DEPS),$(dep)_LIB_NAME)
CLEAN_TARGETS = $(foreach dep, $(UNIQUE_DEPS), $(dep)_CLEAN)
LOCAL_D_FILES = $(LOCAL_O_FILES:.o=.d)
LOCAL_TEST_D_FILES = $(LOCAL_TEST_O_FILES:.o=.d) $(TEST_RUNNER:.o=.d)
DEP_LIB_DIRS = $(foreach dep, $(DEPS) LOCAL, $($(dep)_LIB_DIR))
TEST_DEP_LIB_DIRS = $(foreach dep, $(TEST_DEPS) LOCAL LOCAL_TEST, $($(dep)_LIB_DIR))
UNIQUE_ASSEMBLE_TARGETS = $(sort $(ASSEMBLE_TARGETS) $(ASSEMBLE_TEST_TARGETS))
UNIQUE_DEPS = $(sort $(DEPS) $(TEST_DEPS))
LOCAL_LIB = $(if $(LOCAL_LIB_NAME), $(LOCAL_LIB_DIR)/lib$(LOCAL_LIB_NAME).a)
LOCAL_TEST_LIB = $(if $(LOCAL_TEST_LIB_NAME), $(LOCAL_TEST_LIB_DIR)/lib$(LOCAL_TEST_LIB_NAME).a)
EXE_TARGETS = $(foreach dep,$(EXE_DEPS),$(dep)_EXE_NAME)
INSTALL_TARGETS = $(foreach dep,$(EXE_DEPS),$(dep)_INSTALL)
export PROJECTS += $(PROJECT)
# PHONY targets get remade even if there exists an up-to-date file with the same name.
.PHONY: default clean compile assemble link submit
# Targets for mortals
default: link
clean: $(CLEAN_TARGETS) LOCAL_CLEAN
compile: $(DEPS) $(LOCAL_D_FILES) $(LOCAL_O_FILES)
assemble: compile $(ASSEMBLE_TARGETS) $(LOCAL_LIB)
link: assemble $(EXE_TARGETS) $(EXE_NAME)
install: $(INSTALL_TARGETS) $(if $(EXE_NAME), LOCAL_INSTALL)
submit: link
qsub $(PROJECT).qsub
# Targets for make
# Invoking sub projects
$(UNIQUE_DEPS): MAKE_TARGET = $(if $(filter %_TEST, $#), compile-tests, compile)
$(UNIQUE_DEPS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($#_DIR) && $(MAKE) $(MAKE_TARGET))
# First, remove the _LIB_NAME attached by ASSEMBLE_TARGETS, a
$(UNIQUE_ASSEMBLE_TARGETS): DEP_NAME = $(#:_LIB_NAME=)
$(UNIQUE_ASSEMBLE_TARGETS): MAKE_TARGET = $(if $(filter %_TEST, $(DEP_NAME)), assemble-tests, assemble)
$(UNIQUE_ASSEMBLE_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) $(MAKE_TARGET))
# First, remove the _EXE_NAME attached by EXE_TARGETS, a
$(EXE_TARGETS): DEP_NAME = $(#:_EXE_NAME=)
$(EXE_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) link)
$(CLEAN_TARGETS): DEP_NAME = $(#:_CLEAN=)
$(CLEAN_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) clean)
$(INSTALL_TARGETS): DEP_NAME = $(#:_INSTALL=)
$(INSTALL_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) install)
#Local stuff
# The rule to change either a '.c' or a '.m' to a '.o'
#%.o : %.c %.d %.cc %.cpp
.cc.o .cpp.o .c.o:
#echo "Compiling \"$<\""
#$(CCC) -c $(C_FLAGS) $< -o $#
.cc.d .cpp.d .c.d :
#echo "Creating dependency for \"$<\""
# #$(CCC) $(WARNINGS) $(INCLUDE_DIRS) -MM $< -o $#
# This foogly hack because gcc seems to have issues with emitting the correct target/dependency names of
# files in sub-dirs of the current dir (specifically, it doesn't add the sub-dir to the target
# name, and insists on adding the directory to the dependencies) which ends up breaking dependencies...)
#dependLine=$$( $(CCC) $(C_FLAGS) $(INCLUDE_DIRS) -MM $< ); \
dirName=$$( dirname $< | $(SED) "s/\//\\\\\//g" ); \
dependLine=$$( echo $${dependLine} | $(SED) "s/ $${dirName}\// /g" ); \
oFile=$$( echo $${dependLine} | $(SED) "s/:.*//" ); \
dependencies=$$( echo $${dependLine} | $(SED) "s/.*://" ); \
echo $${oFile} $${oFile%.o}.d: $${dependencies} | $(SED) "s/ \\\//g" > $#
$(UNIQUE_ASSEMBLE_TARGETS): DEP_NAME = $(#:_LIB_NAME=)
$(UNIQUE_ASSEMBLE_TARGETS): MAKE_TARGET = $(if $(filter %_TEST, $(DEP_NAME)), assemble-tests, assemble)
$(UNIQUE_ASSEMBLE_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) $(MAKE_TARGET))
# First, remove the _EXE_NAME attached by EXE_TARGETS, a
$(EXE_TARGETS): DEP_NAME = $(#:_EXE_NAME=)
$(EXE_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) link)
$(CLEAN_TARGETS): DEP_NAME = $(#:_CLEAN=)
$(CLEAN_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) clean)
$(INSTALL_TARGETS): DEP_NAME = $(#:_INSTALL=)
$(INSTALL_TARGETS):
$(if $(findstring $(DEP_NAME), $(PROJECTS)),,cd $($(DEP_NAME)_DIR) && $(MAKE) install)
#Local stuff
# The rule to change either a '.c' or a '.m' to a '.o'
#%.o : %.c %.d %.cc %.cpp
.cc.o .cpp.o .c.o:
#echo "Compiling \"$<\""
#$(CCC) -c $(C_FLAGS) $< -o $#
.cc.d .cpp.d .c.d :
#echo "Creating dependency for \"$<\""
# #$(CCC) $(WARNINGS) $(INCLUDE_DIRS) -MM $< -o $#
# This foogly hack because gcc seems to have issues with emitting the correct target/dependency names of
# files in sub-dirs of the current dir (specifically, it doesn't add the sub-dir to the target
# name, and insists on adding the directory to the dependencies) which ends up breaking dependencies...)
#dependLine=$$( $(CCC) $(C_FLAGS) $(INCLUDE_DIRS) -MM $< ); \
dirName=$$( dirname $< | $(SED) "s/\//\\\\\//g" ); \
dependLine=$$( echo $${dependLine} | $(SED) "s/ $${dirName}\// /g" ); \
oFile=$$( echo $${dependLine} | $(SED) "s/:.*//" ); \
dependencies=$$( echo $${dependLine} | $(SED) "s/.*://" ); \
echo $${oFile} $${oFile%.o}.d: $${dependencies} | $(SED) "s/ \\\//g" > $#
$(LOCAL_LIB): compile $(ASSEMBLE_TARGETS)
#echo Assembling $(LOCAL_LIB_NAME)...
#ar rs $(LOCAL_LIB) $(LOCAL_O_FILES)
# Create the executable
$(EXE_NAME): assemble
#echo Linking $(EXE_NAME)...
#$(CCC) -o $(EXE_NAME) $(L_FLAGS)
# Erase all object files, the dependencies file, the core file and the executable, then rebuild everything
LOCAL_CLEAN:
#echo Cleaning $(PROJECT)...
#rm -f $(LOCAL_O_FILES) $(LOCAL_TEST_O_FILES) $(LOCAL_LIB) $(LOCAL_TEST_LIB) $(EXE_NAME) $(TEST_EXE_NAME) $(LOCAL_D_FILES) $(LOCAL_TEST_D_FILES) $(TEST_RUNNER) $(TEST_RUNNER:.o=.d) core*
ifeq (,$(findstring clean,$(MAKECMDGOALS)))
-include $(LOCAL_O_FILES:.o=.d) $(LOCAL_TEST_O_FILES:.o=.d)
endif
The paths to my mpicxx compiler (needed for the cluster, and for those unfamiliar, it wraps gcc) are correct, as evidenced by the fact that it does compile, it just won't link. Similarly, my boost library paths seem functional, the -lboost_mpi flag gets caught properly.
At this point, my question has extended to be for my own education based on how this makefile works/intends to work. Ultimately the entirely obvious/simple command:
mpicxx boosttest.cpp -L ~/boost/stage/lib/ -lboost_mpi -lboost_serialization -o test
however I want to get a proper makefile going as once I get past this test case verifying Boost.MPI's equivalent of a hello world, I'll be moving on to projects involving my full source code, 20+ files with cross dependencies, etc. Any help or intuition would be greatly appreciated.

Answer 1

Based on the suggestion of #Oktalist above, I was able to find something that works, at least for the single-file case, but I can't see why it won't work when I extend this to multiple files. I'm still at a loss why this worked in the past but not now, but perhaps I changed something I wasn't tracking.
The correction is near the end, in this block:
# Create the executable
$(EXE_NAME): assemble
#echo Linking $(EXE_NAME)...
#$(CCC) $(L_FLAGS) $(LOCAL_LIB) -o $(EXE_NAME)