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c++linuxmultithreadingmakefilehost

Makefile for host & target

My question is about compiling error on linux. Every time I try to compile the program it gives me this error. I tried different things without luck.

*** No rule to make target '/pthread.d', needed by '/thread.exe'. Stop.

The makefile for the program ( pthread is as follow:

SOURCES=pthread.cpp   
OBJECTS=$(addprefix $(BUILD_DIR)/, $(SOURCES:.cpp=.o))   
DEPS=$(addprefix $(BUILD_DIR)/, $(SOURCES:.cpp=.d))   
EXE=thread.exe    
CXXFLAGS=-I.    
LIBS=-pthread    

//Making for host > make ARCH=host
ifeq ($(ARCH),host)    
CXX=g++    
BUILD_DIR=build/host    
BIN_DIR=bin/host    
endif    


//Making for target > make ARCH= target    
ifeq ($(ARCH),target)    
CXX=arm-rpizw-g++    
BUILD_DIR=build/target    
BIN_DIR=bin/target    
endif    

all: $(BIN_DIR)/$(EXE)    

$(BIN_DIR)/$(EXE): $(DEPS) $(OBJECTS)    
    mkdir -p $(BIN_DIR)    
    $(CXX) $(CXXFLAGS) -o $@ $(OBJECTS)    

$(BUILD_DIR)/%.d: %.cpp    
    mkdir -p $(BUILD_DIR)     
    $(CXX) -MT$(@:.d=.o) -MM $(CXXFLAGS) $^ > $@    

$(BUILD_DIR)/%.o: %.cpp    
    mkdir -p $(BUILD_DIR)    
    $(CXX) -c $< -o $@ $(CXXFLAGS)    

ifneq ($(MAKECMDGOALS), $(filter $(MAKECMDGOALS),clean help))    
-include $(DEPS)    
endif    

clean:    
    -rm -rf bin/    
    -rm -rf build/
Solution

  • You likely have spaces after BUILD_DIR=build/target. Thus, $(DEPS) resolves to:

     build/target   /pthread.d

    ..., and thus make will try to make /pthread.d (and build/target...). When assigning a value, make discards any preceding spaces, but not trailing spaces. It will drop a trailing comment, but it will not drop whitespace between the end of the line and the comment.

    For debugging this type of problem, it's often useful to add $(info) lines into your makefile as so: 

    $(info DEPS=_$(DEPS)_)

    and then run to see if there are any unexpected values.