Makefile unable to link libraries during runtime

Question

So I am using nvidia's deepstream sdk and trying to modify the makefile of one of the sample examples given as I wish to link and add my own libraries. This is the makefile being employed where I am setting the path of the CUSTOM_LIB to point to the location of my library. The issue is the project gets compiled successfully but during run time, its unable to find the custom library. I performed ldd on the executable generated and there also it was showing the library as 'not found'. I think it's something to do with rpath but I am not sure about that.

APP:= sample

TARGET_DEVICE = $(shell gcc -dumpmachine | cut -f1 -d -)

NVDS_VERSION:=4.0

LIB_INSTALL_DIR?=/opt/nvidia/deepstream/deepstream-$(NVDS_VERSION)/lib/

ifeq ($(TARGET_DEVICE),aarch64)
  CFLAGS:= -DPLATFORM_TEGRA
endif

CUDA_VER:=10.0
CC:=g++

SRCS:= $(wildcard ../src/*.c)
#SRCS+= $(wildcard ../../apps-common/src/*.c)
#SRCS+=

INCS:= $(wildcard ../include/*.h)

PKGS:= gstreamer-1.0 gstreamer-video-1.0 x11 opencv

OBJS:= $(SRCS:.c=.o)

CFLAGS+= -I../include -I/usr/include -I$(CUSTOM_LIB)/include -I/usr/local/cuda-10.0/targets/aarch64-linux/include/ -I/usr/include/jsoncpp  -DDS_VERSION_MINOR=0 -DDS_VERSION_MAJOR=4 -fpermissive -Wnarrowing

LIBS+= -L$(LIB_INSTALL_DIR)  -L/usr/lib/aarch64-linux-gnu -L$(CUSTOM_LIB)/lib -L/usr/lib/aarch64-linux-gnu/ -lcurl -letlic -letolm -lssl -lcrypto -llogger -lpthread -lsqlite3 -ljsoncpp -lnvdsgst_meta -lnvbufsurface -lnvbufsurftransform -lnvds_meta -lnvdsgst_helper -lnvds_utils -lm -L/usr/local/cuda-$(CUDA_VER)/lib64/  -lcudart \
-lgstrtspserver-1.0 -Wl,-rpath,$(LIB_INSTALL_DIR)

CFLAGS+= `pkg-config --cflags $(PKGS)`

LIBS+= `pkg-config --libs $(PKGS)`

all: $(APP)

debug: CXXFLAGS += -DDEBUG -g
debug: CFLAGS += -DDEBUG -g
debug: $(APP)

%.o: %.c $(INCS) Makefile
    $(CC) -c -o $@ $(CFLAGS) $<


$(APP): $(OBJS) Makefile
    $(CC) -o $(APP) $(OBJS) $(LIBS)

clean:
    rm -rf $(OBJS) $(APP)

Answer 1

You need to set rpath to a colon-separated list of directories where your libraries are found. You only add LIB_INSTALL_DIR but not CUSTOM_LIB_DIR. Generally everything you pass to -L you need to pass to -rpath too, unless there is a specific reason not to. For example, if you are building a package that has more than a single library and you are going to install in a standard place like /usr/lib, you don't have to add the directory where libraries temporarily live to -rpath. If you are going to install to a non-standard directory, add that directory.