How to modify library in makefile - c++

I have a makefile that I need to modify to include the path to libraries.I am trying to run program given to me by someone else. I'm really confused on how the makefile works and don't understand what the previous lines are.
These are the directions given to me to modify the makefile:
Change the lines:
INCS = -I"../../LIB/libpca/include"
LIBS = -L"../../LIB/libpca/build" -lpca -larmadillo
in the Makefile to represent the folder where you installed the libpca and armadillo libraries.
Now I now what my new paths are:
Desktop/PCA-CD/Libraries
but I don't understand what is is that I really need to change.
Here is what the makefile looks like:
PROG = CD
UNAME := $(shell uname)
ifeq ($(UNAME), Darwin)
CXX = clang++ -stdlib=libc++
else
CXX = g++
endif
FLAGS = -O0 -g3 -Wall -std=c++0x -pthread
INCS = -I"../../LIB/libpca/include"
LIBS = -L"../../LIB/libpca/build" -lpca -larmadillo
SRCS = CD.cpp
RM = rm -f
all :
$(CXX) $(FLAGS) $(INCS) $(SRCS) $(LIBS) -o $(PROG)
# $(CXX) $(FLAGS) $(SRCS) -o $(PROG)
clean :
$(RM) $(PROG)
Thanks for any help provided.

I think they're suggesting to change the line:
INCS = -I"../../LIB/libpca/include"
LIBS = -L"../../LIB/libpca/build" -lpca -larmadillo
to
INCS = -I"Desktop/PCA-CD/Libraries/include"
LIBS = -L"Desktop/PCA-CD/Libraries/build" -lpca -larmadillo
Notice that Desktop/PCA-CD/Libraries is a relative path, and assumes that the library is stored in the subdirectory of the build directory. From your build directory, try running ls Desktop/PCA-CD/Libraries/build, to confirm it is right path. If it's not, replace it with the absolute path of the directory where you installed the library.

Related

Makefile unable to link libraries during runtime

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)
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.

makefile not finding header file from -I include path

I have the makefile given below. When I do make I get the following error
cc -c -o timing.o timing.c
test_c.c:5:17: fatal error: test.h: No such file or directory
#include "test.h"
I have manually verfied that test.h is present in ../include path. I am not sure why this is not finding the header file.It would be great if someone could help.Also I would expect g++ instead of cc
# Makefile template for shared library
CXX = g++ # C++ compiler
CXXFLAGS = -fPIC -Wall -Wextra -O2 -g -I../include #CXX flags
LDFLAGS = -lboost_system -shared # linking flags
RM = rm -f # rm command
TARGET_LIB = libtest.a # target lib
C_SRCS := test_a.c test_b.c
CPP_SRCS := test_c.cpp test_d.cpp
OBJS := $(C_SRCS:.c=.o) $(CPP_SRCS:.cpp=.o)
.PHONY: all
all: ${TARGET_LIB}
$(TARGET_LIB): $(OBJS)
$(CXX) $(CXXFLAGS) ${LDFLAGS} -o $# $^
.PHONY: clean
clean:
-${RM} ${TARGET_LIB} ${OBJS}
~
You have not written a rule for building timing.o from timing.c, so Make uses the default rule it has for that.
But that rule uses CFLAGS, not CXXFLAGS. The CXXFLAGS variable appears in the rule for building object files from C++ sources.
So modify CFLAGS instead of CXXFLAGS, and it should work.

Cannot properly use the Makefile for some course files

I am trying to work through the following http://www.cs.columbia.edu/~keenan/Projects/DGPDEC/paper.pdf. The following source files are used to illustrate what is going on https://github.com/dgpdec/course. Now I cannot get it to work. Here is what I tried:
First I went into the folder 'basecode', edited the Makefile to have the right include and library paths. Then I want to make but it gives me the error
'ostream’ in namespace ‘std’ does not name a type
I looked for this error online but I could not find a solution to the problem. In the included file libddg_userguide.pdf it says that I should edit the Makefile in root libddg folder but I don't know which folder that is. I am sorry for the kind of nooby question but I am really stuck and have been trying for a long time. Here is the Makefile I used (in the Basecode folder) for reference:
##########################################################################################
# Specify library locations here (add or remove "#" marks to comment/uncomment lines for your platform)
# Linux
DDG_INCLUDE_PATH = -I/usr/include/ -I/usr/local/include -I/usr/include/suitesparse
DDG_LIBRARY_PATH = -L/usr/lib -L/usr/local/lib
DDG_BLAS_LIBS = -llapack -lblas -lgfortran
DDG_SUITESPARSE_LIBS = -lspqr -lcholmod -lmetis -lcolamd -lccolamd -lcamd -lamd -lm
DDG_OPENGL_LIBS = -lglut -lGL -lGLU -lX11
########################################################################################
TARGET = ddg
CC = g++
LD = g++
CFLAGS = -O3 -Wall -Werror -ansi -pedantic $(DDG_INCLUDE_PATH) -I./include -I./src
LFLAGS = -O3 -Wall -Werror -ansi -pedantic $(DDG_LIBRARY_PATH)
LIBS = $(DDG_OPENGL_LIBS) $(DDG_SUITESPARSE_LIBS) $(DDG_BLAS_LIBS)
########################################################################################
## !! Do not edit below this line
HEADERS := $(wildcard include/*.h)
SOURCES := $(wildcard src/*.cpp)
OBJECTS := $(addprefix obj/,$(notdir $(SOURCES:.cpp=.o)))
all: $(TARGET)
$(TARGET): $(OBJECTS)
$(LD) $(OBJECTS) -o $(TARGET) $(CFLAGS) $(LFLAGS) $(LIBS)
obj/%.o: src/%.cpp ${HEADERS}
$(CC) -c $< -o $# $(CFLAGS)
clean:
rm -f $(OBJECTS)
rm -f $(TARGET)
rm -f $(TARGET).exe
Thanks in advance for any help!
It means there is a bug in the code: a header's missing because someone made an assumption.
Your particular toolchain does not satisfy that assumption.
Find the problematic file (you didn't say which it is) and add #include <ostream> to it.
(course/Connection/include/DenseMatrix.h appears to be one such file; there may be others.)
N.B. I must say that, despite the bug, overall this is incredibly good C++ code for a University course. I'm impressed.

Building multiple shared libraries with one Makefile

I'm trying to build multiple shared libraries in one makefile. This is what I'm using to build one shared library:
CC = gcc # C compiler
PWD := $(shell pwd)
CFLAGS = -fPIC -Wall -Wextra -O2 -g # C flags
LDFLAGS = -shared # linking flags
RM = rm -f # rm command
CFLAGS += $(DFLAGS)
TARGET_LIB := lib1.so # target lib
#TARGET_LIB += lib2.so
SRCS := lib1.c # source files
#SRCS += lib2.c # source files
OBJS = $(SRCS:.c=.o)
.PHONY: all
all: $(TARGET_LIB)
$(TARGET_LIB): $(OBJS)
$(CC) $(INC) $(LDFLAGS) $(CFLAGS) -o $# $^
However, I can't just uncomment the lines for lib2 and have it being built as well. It's likely because $(TARGET_LIB): $(OBJS) expands to lib1.so lib2.so : lib1.o lib2.o which isn't what I want.
Instead, I want something like
lib1.so : lib1.o
lib2.so : lib2.o
But I'm not sure how to do so or what it is called. Can someone tell me what to do to achieve what I'm looking for?
EDIT: I should have been more clear. I realize you can add more targets to build these. But is there a way to do it without having to write a new target everytime I want to add a new library?
Thanks.
You can do something like this -
all : lib1.so lib2.so
and provide rules to make lib1.so and lib2.so
You can separate sources of two libraries into different directories. It also may help in further maintenance of your libraries. Then use one make file which will trigger corresponding sub-makefiles. I may be better than one big makefile
You can do it by separating targets like this:
CC = gcc # C compiler
PWD := $(shell pwd)
CFLAGS = -fPIC -Wall -Wextra -O2 -g # C flags
LDFLAGS = -shared # linking flags
RM = rm -f # rm command
CFLAGS += $(DFLAGS)
TARGET_LIB1 = lib1.so # target lib
TARGET_LIB2 = lib2.so
TARGET_LIBS = $(TARGET_LIB1) $(TARGET_LIB2)
SRCS1 = lib1.c # source files
SRCS2 = lib2.c # source files
SRCS = $(SRCS1) $(SRCS2)
OBJS1 = $(SRCS1:.c=.o)
OBJS2 = $(SRCS2:.c=.o)
OBJS = $(OBJS1) $(OBJS2)
.PHONY: all
all: $(TARGET_LIBS)
$(TARGET_LIB1): $(OBJS1)
$(CC) $(INC) $(LDFLAGS) $(CFLAGS) -o $# $^
$(TARGET_LIB2): $(OBJS2)
$(CC) $(INC) $(LDFLAGS) $(CFLAGS) -o $# $^
The implicit rules are for that. Read about them in the GNU Make manual.
Replace
$(TARGET_LIB): $(OBJS)
with
%.so: %.c

Linking boost libraries in makefile under cygwin

I'm trying to link my program with boost libraries using makefile with cygwin. Here is my makefile:
CXX = g++
CXXFLAGS = -Wno-signed-compare -Wall -std=c++11 -funsigned-char -I /cygdrive/e/boost/include/boost-1_55/boost
LNKFLAGS = -L cygdrive/e/boost/lib
SRCDIR = src
OUTDIR = bin
EXEC = $(OUTDIR)/prg
SOURCES = $(wildcard src/*.cpp)
OBJECTS := $(SOURCES:$(SRCDIR)/%.cpp=$(OUTDIR)/%.o)
all: $(EXEC)
$(EXEC): $(OBJECTS)
$(CXX) $(LNKFLAGS) $(OBJECTS) -o $(EXEC) -l boost_thread
$(OBJECTS): $(OUTDIR)/%.o : $(SRCDIR)/%.cpp
mkdir -p $(OUTDIR)
$(CXX) $(CXXFLAGS) -c -O3 $< -o $#
clean:
rm -rf $(OUTDIR)
.PHONY: clean
Result:
$ make
g++ -L cygdrive/e/boost/lib bin/test.o -o bin/prg -l boost_thread
c:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: cannot find -lboost_thread
What's wrong? What should I specify?
In your Makefile the library search path is relative, but should be absolute in this case.
LNKFLAGS = -L/cygdrive/e/boost/lib
Check if /cygdrive/e/boost/lib really contains Boost libraries built with the GCC toolchain.
libboost_thread.a or libboost_thread.so will work.
Libraries built with the Visual C++ toolchain ending with .lib or .dll will not work.
Check if the filename matches.
-lboost_thread requires that the library is named either libboost_thread.a or libboost_thread.so.
libboost_thread-mt.a or the like will not work.
You may find my answer to a related question helpful.