How to link opencv lib in a given directory in makefile

Question

I'm compiling a project and I want to link it to the opencv in a given directory, not the system directory like /usr/local/lib/libopencv

In the end is the default makefile, which links to the system directory /usr/local/lib .

The opencv I want to link is located in directory ../../third_party/opencv/ , with ../../third_party/opencv/include/ and ../../third_party/opencv/lib/ . The absolute path is /home/somepath/third_party/opencv/ .

How shall I modify the makefile to have the project link to the opencv I want to use, instead of the system version?

Currently, when I compile the project and use ldd to check its dependency, say ldd evaluate | grep opencv ldd evaluate | grep opencv ， I got the following. It means the project still links to the system version, not my chosen one.

libopencv_highgui.so.3.0 => /usr/local/lib/libopencv_highgui.so.3.0 (0x00007efc72527000)
libopencv_imgcodecs.so.3.0 => /usr/local/lib/libopencv_imgcodecs.so.3.0 (0x00007efc7217a000)
libopencv_imgproc.so.3.0 => /usr/local/lib/libopencv_imgproc.so.3.0 (0x00007efc711f8000)
libopencv_core.so.3.0 => /usr/local/lib/libopencv_core.so.3.0 (0x00007efc70565000)

Thank you for helping me!!!

PROJECT_NAME:= evaluate

# config ----------------------------------

INCLUDE_DIRS := include
LIBRARY_DIRS := lib

COMMON_FLAGS := -DCPU_ONLY
CXXFLAGS := -std=c++11 -fopenmp -D_GLIBCXX_USE_CXX11_ABI=0

LDFLAGS := -fopenmp -Wl,-rpath,./lib

OPENCV = `pkg-config opencv --cflags --libs`
LIB = $(OPENCV)
BUILD_DIR := build

# make rules -------------------------------
CXX ?= g++
BUILD_DIR ?= ./build

LIBRARIES += opencv_core opencv_highgui opencv_imgproc #opencv_imgcodecs

CXXFLAGS += $(COMMON_FLAGS) $(foreach includedir,$(INCLUDE_DIRS),-I$(includedir))
LDFLAGS +=  $(COMMON_FLAGS) $(foreach includedir,$(LIBRARY_DIRS),-L$(includedir)) $(foreach library,$(LIBRARIES),-l$(library))
SRC_DIRS += $(shell find * -type d -exec bash -c "find {} -maxdepth 1 \( -name '*.cpp' -o -name '*.proto' \) | grep -q ." \; -print)
CXX_SRCS += $(shell find src/ -name "*.cpp")
CXX_TARGETS:=$(patsubst %.cpp, $(BUILD_DIR)/%.o, $(CXX_SRCS))
ALL_BUILD_DIRS := $(sort $(BUILD_DIR) $(addprefix $(BUILD_DIR)/, $(SRC_DIRS)))

.PHONY: all
all: $(PROJECT_NAME)

.PHONY: $(ALL_BUILD_DIRS)
$(ALL_BUILD_DIRS):
    @mkdir -p $@

$(BUILD_DIR)/%.o: %.cpp | $(ALL_BUILD_DIRS)
    @echo "CXX" $<
    @$(CXX) $(CXXFLAGS) -c -o $@ $<

$(PROJECT_NAME): $(CXX_TARGETS)
    @echo "CXX/LD" $@
    @$(CXX) -o $@ $^ $(LDFLAGS) $(LIB)

.PHONY: clean
clean:
    @rm -rf $(CXX_TARGETS)
    @rm -rf $(PROJECT_NAME)
    @rm -rf $(BUILD_DIR)

Answer 1

One way is to modify next lines

INCLUDE_DIRS := ../../third_party/opencv/include/ include
LIBRARY_DIRS := ../../third_party/opencv/lib/ lib

Or second different way is to add -I and -L options to next lines

CXXFLAGS := -std=c++11 -fopenmp -D_GLIBCXX_USE_CXX11_ABI=0 -I../../third_party/opencv/include/
LDFLAGS := -fopenmp -Wl,-rpath,./lib -L../../third_party/opencv/lib/