Makefile - .o: file not recognized: File truncated? - c++

Question

I'm just learning GNU make, but I'm having trouble linking when using .d (dependency) files. Can anyone point me in the right direction with this error:
...../part1.o: file not recognized: File truncated
recipe for target 'bin/target/prog' failed
It's a simple program containing: main.cpp, part1.cpp, part1.h, part2.cpp, part2.h
Where part1 and part2 have a method to print something.
This is from terminal when running make:
I don't get why I'm getting a warning for using #pragma once?
stud#GoldenImageASE:~/Desktop/ISU/L1/2$ make ARCH=target -f Makefile.th
Compiling...part2.cpp
arm-devkit-g++ -MTbuild/target/part2.o -MM -I. part2.cpp > build/target/part2.d
Compiling...part1.cpp
arm-devkit-g++ -MTbuild/target/part1.o -MM -I. part1.cpp > build/target/part1.d
Compiling...main.cpp
arm-devkit-g++ -MTbuild/target/main.o -MM -I. main.cpp > build/target/main.d
object file....main.o
arm-devkit-g++ -I. -c main.cpp part1.h part2.h > build/target/main.o
part1.h:1:9: warning: #pragma once in main file
#pragma once
^
part2.h:1:9: warning: #pragma once in main file
#pragma once
^
object file....part1.o
arm-devkit-g++ -I. -c part1.cpp > build/target/part1.o
object file....part2.o
arm-devkit-g++ -I. -c part2.cpp > build/target/part2.o
arm-devkit-g++ -I. -o build/target/main.o build/target/part1.o build/target/part2.o -o prog
build/target/part1.o: file not recognized: File truncated
collect2: error: ld returned 1 exit status
Makefile.th:27: recipe for target 'bin/target/prog' failed
make: *** [bin/target/prog] Error 1
My Makefile is found below:
# Variables
SOURCES=main.cpp part1.cpp part2.cpp
OBJECTS=$(SOURCES:.cpp=.o)
DEPS=$(SOURCES:.cpp=.d)
EXE=prog
CXXFLAGS =-I.
# Making for host
# > make ARCH=host
ifeq (${ARCH},host)
CXX=g++
BUILD_DIR=build/host
EXE_DIR=bin/host
endif
# Making for target
# > make ARCH= target
ifeq (${ARCH},target)
CXX=arm-devkit-g++
BUILD_DIR=build/target
EXE_DIR=bin/target
endif
$(addprefix ${EXE_DIR}/,$(EXE)): $(addprefix ${BUILD_DIR}/,$(DEPS)) $(addprefix ${BUILD_DIR}/,$(OBJECTS))
# << Check the $(DEPS) new dependency
#mkdir -p $(dir $#)
$(CXX) $(CXXFLAGS) -o $(addprefix ${BUILD_DIR}/,$(OBJECTS))
$(addprefix $(BUILD_DIR)/, %.o): %.cpp
#echo "object file...."$*.o
$(CXX) $(CXXFLAGS) -c $^ > $#
# Rule that describes how a .d ( dependency ) file is created from a .cpp
# Similar to the assigment %. cpp -> %.o
${BUILD_DIR}/%.d: %.cpp
#mkdir -p $(dir $#)
#echo "Compiling..."$<
$(CXX) -MT$(#:.d=.o) -MM $(CXXFLAGS) $^ > $#
debug:
#echo "DEPS: "$(DEPS)"\n"
#echo "OBJ: " $(addprefix ${BUILD_DIR}/,$(OBJECTS))"\n"
#echo "EXE: " $(addprefix ${EXE_DIR}/,$(EXE))"\n"
.PHONY:clean
clean:
rm -f $(EXE) $(addprefix ${BUILD_DIR}/,$(DEPS)) $(addprefix ${BUILD_DIR}/,$(OBJECTS))
ifneq ($(MAKECMDGOALS),clean)
-include $(addprefix ${BUILD_DIR}/,$(DEPS))
endif

Answer 1

You have two unrelated problems. The first one is that you have two conflicting -o options when linking.
The actual problem you ask about is something different, but still related to the -o option: Namely that you don't have one when attempting to create the object files.
When creating the object files, the generated object file is not written to standard output, therefore your redirection will not cause the gcc frontend program to create an object file with the name you think.
For example:
arm-devkit-g++ -I. -c part1.cpp > build/target/part1.o
The above command will create an object file named part1.o in the current directory, and write the (empty) standard output to the file build/target/part1.o. That will leave build/target/part1.o empty, which is what the linker is complaining about (that's what it means when it says the file is truncated).
The command should instead look like
arm-devkit-g++ -I. -c part1.cpp -o build/target/part1.o
Note the use of the -o option to name the output file.
You need to modify the makefile to not use redirection when building the object files.
Also, you should not list the header files when building object files, only the source file you want to build, so the command
arm-devkit-g++ -I. -c main.cpp part1.h part2.h > build/target/main.o
should really be
arm-devkit-g++ -I. -c main.cpp -o build/target/main.o

Answer 2

You're not compiling your object files correctly. g++ doesn't output the files to stdout, it writes them to the local directly. If you want to put the object files in a specific directory, you need to use the -o option:
$(BUILD_DIR)/%.o: %.cpp | $(BUILD_DIR)
$(CXX) $(CXXFLAGS) -c $^ -o $#
^^^^^^
$(BUILD_DIR):
#mkdir -p $#
Also you're building your executable incorrectly. The dependencies are insufficient and you don't have your target listed. You'll want this:
$(EXE_DIR)/$(EXE) : $(addprefix $(BUILD_DIR),$(OBJECTS)) | $(EXE_DIR)
$(CXX) $(CXXFLAGS) -o $# $^
$(EXE_DIR):
#mkdir -p $#
This will create an order-only dependency from your binary on the directory, and correctly build the binary. Note that you shouldn't have a dependency from your target on your .d files. That makes little sense. Instead, your rule for building the .os should simply also build the .ds (that rule suffers the same problem currently as your .o rule):
# build the .o and the .d in one go
$(BUILD_DIR)/%.o : %.cpp | $(BUILD_DIR)
$(CXX) $(CXXFLAGS) -o $# -c $< -MP -MMD -MF $(#:.o=.d)
AS AN EDITORIAL ASIDE, THERE IS THIS COMMON TENDENCY TO WRITE ALL VARIABLES IN MAKEFILES IN SHOUTY_CAPS. THIS IS PROVABLY MUCH MORE DIFFICULT TO READ THAN USING JUST USING snake_case. Lower case letters work just fine.