链接dylib库

Question

我正在尝试将dylib链接到Mac上的makefile，但是Clang给出了这样的消息：

Undefined symbols for architecture x86_64:
"_zbesj_wrap", referenced from:
  sp_bessel::besselJ(double, std::__1::complex<double>) in besselJ.o
"_zbesy_wrap", referenced from:
  sp_bessel::besselJ(double, std::__1::complex<double>) in besselJ.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我在/usr/lib中安装了这个库，在那里我可以看到libcomplex_bessel.0.6.0.dylib和libcomplex_bessel.dylib。这是我的makefile

OBJS = main.o besselJ.o
CC = c++
CFLAGS = -std=c++11 -stdlib=libc++
LIBS = -L/usr/lib -lcomplex_bessel
PROGRAM_NAME = test

all: $(PROGRAM_NAME)
$(PROGRAM_NAME): $(OBJS)
    $(CC) $(CFLAGS) $(OBJS) -o $@
main.o: main.cpp
    $(CC) $(CFLAGS) -c $< -o $@ 
besselJ.o: besselJ.cpp
    $(CC) $(CFLAGS) -c $< -o $@ $(LIBS)

在阅读了其他的问题后，我尝试了-L和-l的不同组合，但都没有效果。抱歉，这是我第一次用外部图书馆.

我把我的makefile改为：

OBJS = main.o besselJ.o
CC = c++
CFLAGS = -std=c++11 -stdlib=libc++
LIBS = -L/usr/lib -lcomplex_bessel
PROGRAM_NAME = test

all: $(PROGRAM_NAME)
$(PROGRAM_NAME): $(OBJS)
    $(CC) $(CFLAGS) $(OBJS) -o $@ $(LIBS)
main.o: main.cpp
    $(CC) $(CFLAGS) -c $< -o $@ 
besselJ.o: besselJ.cpp
    $(CC) $(CFLAGS) -c $< -o $@ 

但我仍然有问题，我得到了这样的信息：

c++ -std=c++11 -stdlib=libc++ main.o besselJ.o -o test -L/usr/lib -lcomplex_bessel
ld: library not found for -lcomplex_bessel
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [test] Error 1

好的，我想我用xcode-select --install解决了这个问题:其他用户在更新库后也遇到了同样的问题。

Answer 1

您需要将库传递给链接器，而不是编译器：

OBJS = main.o besselJ.o
CC = c++
CFLAGS = -std=c++11 -stdlib=libc++
LIBS = -L/usr/lib -lcomplex_bessel
PROGRAM_NAME = test

all: $(PROGRAM_NAME)
$(PROGRAM_NAME): $(OBJS)
    $(CC) $(OBJS) -o $@ $(LIBS)
main.o: main.cpp
    $(CC) $(CFLAGS) -c $< -o $@ 
besselJ.o: besselJ.cpp
    $(CC) $(CFLAGS) -c $< -o $@