OS X 10.9：无法调试使用g ++制作的c ++动态库

Question

I've read multiple posts here relating to dynamic libraries on os x and debugging with gdb. But I still can't figure out why I can't debug a simple test case.

The main issue is that when I start up GDB it never loads any shared libraries.

Update: I've tried this with GDB from macports, from homebrew, and built from source and the behavior is the same.

I have a class that I compile into a library.

Test.hpp

class Test {
public:
  void set(int i);
  void out() const;
private:
  int i;
};

Test.cpp

#include "Test.hpp"
#include <iostream>

void Test::set(int ii) { i = ii; }

void Test::out() const {
  auto j = i * 100;
  std::cout << i << ", " << j << "\n";
  ++j;
  std::cout << i << ", " << j << "\n";
}

I compile it and create a library with g++. Note: the behavior is the same with macports gcc and the gcc from xcode.

/opt/local/bin/g++-mp-4.8 -O0 -g -ggdb -Wall -c -std=c++11 -o Test.o Test.cpp
/opt/local/bin/g++-mp-4.8 -dynamiclib -o libTest.dylib Test.o

Then I test it with this simple main

#include "Test.hpp"

int main() {
  Test t;
  auto x = 4;
  t.set(x);
  t.out();
  return 0;
}

This is compiled and linked with

/opt/local/bin/g++-mp-4.8 -O0 -g -ggdb -Wall -c -std=c++11 -o main.o main.cpp
/opt/local/bin/g++-mp-4.8 -L . -o testing main.o -lTest

Everything compiles and runs as expected. But when I try to debug this with gdb (installed from macports, or installed from source, the behavior is the same), I have problems.

As I step through main, if I call info sharedlibrary it always says "No shared libraries loaded at this time.", so it apparently never loads libTest.dylib . Therefore, I can't step into any of the Test member functions or create breakpoints anywhere in libTest.dylib .

Answer 1

Indeed ggdb installed from macports for some reason does not respect the DYLD_LIBRARY_PATH. However, if you "patch" your executable with the correct paths for the .dylibs you should be able to debug with ggdb. Take a look at this question and especially the answer by Akos Cz.