Question

I am trying to add a project’s (call it b) code to a different project(call it a). Both projects are compile and run separately. I just copied the folder of project b into project a‘s folder. In project a‘s Makefile, I added the lines to compile project b with it. It compiles fine. Now I want to use b‘s code. But when I try to #include "/bfolder/somefile.h", it cannot find the file. What am I missing about this? If I can just #include "somefileinsamedirectory.h", why can’t I do #include "/bfolder/somefile.h"?`

This is a ‘s Makefile that I have edited to include the irobot_driver code.

INCLUDE = -I/usr/X11R6/include -I/home/sterling/irobot_driver
CC=g++ 
CFLAGS=-w -D LINUX -fpermissive 
CFLAGS_R= -w -D LINUX -O3 -fpermissive 
CFLAGS_D=-w -D LINUX -fpermissive 
OBJ= obj
OBJ_DEBUG= obj_debug
OBJDIR= release
SRCDIR= src

LDFLAGS= -L/usr/X11R6/lib$(LIBSELECT) -lGL -lfltk -lfltk_gl -lXext -lX11 -lglut -lGLU -lfltk_images

SOURCES_RAW=codeprofiler.cpp gametimer.cpp timer.cpp timeprofile.cpp vector4.cpp matrix.cpp agent.cpp agentcontroller.cpp dummy.cpp evader.cpp pursuer.cpp goal.cpp player.cpp graphdata.cpp graph.cpp cubiccoefs.cpp segment.cpp trajectory.cpp anode.cpp arrayvector4.cpp color.cpp drawcomponent.cpp drawcontroller.cpp flags.cpp global.cpp map_analyzer.cpp minheap.cpp node.cpp quadtree.cpp queue.cpp results.cpp sensor.cpp settings.cpp utility.cpp world.cpp gui.cpp main.cpp logger.cpp parameters.cpp counter.cpp polygon.cpp line.cpp

TARGET:= pursuit_evasion
TARGETD:= pursuit_evasion_d
TARGETP:= pursuit_evasion_p
TARGETW32:= pursuit_evasion_w32

OBJECTS:=$(SOURCES_RAW:.cpp=.o)
OBJECTS:=$(patsubst %.o,$(OBJDIR)/%.o, $(OBJECTS))

SOURCES:=$(SOURCES_RAW)
SOURCES:=$(patsubst %.cpp,$(SRCDIR)/%.cpp, $(SOURCES))

OBJ_DEBUG:=$(SOURCES_RAW:.cpp=.o)
OBJ_DEBUG:=$(patsubst %.o,debug/%.o, $(OBJ_DEBUG))

OBJECTS_P:=$(SOURCES_RAW:.cpp=.o)
OBJECTS_P:=$(patsubst %.o,profile/%.o, $(OBJECTS_P))

OBJDIR=obj

all: $(TARGET)

#--- Release 
$(TARGET): $(OBJECTS)
    $(CC) -w -D LINUX $(INCLUDE) $^ -o $@ $(LDFLAGS)
    cd /home/sterling/irobot_driver; sudo make -j2

release/%.o: src/%.cpp
    $(CC) -c $< $(CFLAGS_R) -o $@ 

#--- Debug
debug: $(TARGETD)

$(TARGETD): $(OBJ_DEBUG)
    $(CC) -w -D LINUX $(INCLUDE) $^ -o $@ $(LDFLAGS)
    cd /home/sterling/irobot_driver; sudo make -j2

debug/%.o: src/%.cpp
    $(CC) -c -g $< $(CFLAGS)-o $@ 

#-- Profile
profile: $(TARGETP)

$(TARGETP): $(OBJECTS_P)
    $(CC) -w -g -pg -D LINUX $(INCLUDE) $^ -o $@ $(LDFLAGS)

profile/%.o: src/%.cpp
    $(CC) -c -g -pg $< $(CFLAGS)-o $@ 

win32: $(TARGETW32)

$(TARGETW32): $(OBJECTS)
    $(CC) -w -D WIN32 $(INCLUDE_W32) $^ -o $@ $(LDFLAGS)

.PHONY : clean
clean:
    rm -f release/*.o
    rm -f debug/*.o
    rm -f profile/*.o
    rm -f $(TARGET) $(TARGETD) $(TARGETP)
    cd /home/sterling/irobot_driver; make clean;

The #include “/the/whole/path/to/a/file” that works is –

#include "/home/sterling/irobot_driver/robot_driver_agent.h"

Answer 1

You can, but when you declare the path starting with /some/path/to/file.h it’s going to really look for the file at /some/path/to/file.h. If instead you want the bfolder/somefile.h, remove the / from the beginning.

Also, in general, if b is a library that you want to use, it is best to keep it in whatever folder it resides, and include and link using the -I, -L and -l options of gcc, or similar options of other compilers. This way, if you update b you don’t need to copy it to every project that uses it.