[Boost Error] gcc.compile.c++ bin.v2/libs/python/build/gcc-7/release/link-static/threading-multi/converter/builtin_converters.o libs/python/src/converter/builtin_converters.cpp: In function ‘void* boost::python::converter::{anonymous}::convert_to_cstring(PyObject)’: libs/python/src/converter/builtin_converters.cpp:51:35: error: invalid conversion from ‘const void’ to ‘void*’ [-fpermissive] return PyUnicode_Check(obj) ? _PyUnicode_AsString(obj) : 0;

[Goal]

Boost를 python 버전과 함께 install 할 때 발생하는 문제를 해결할 수 있다.

[Cause]

Boost python 라이브러리를 설치할 때, python version에 따른 경로를 찾지 못하여 문제가 발생하였기 때문에 boost package를 일부 수정

[Process]

[Step 1] boost package 내부 코드인 ~/boost_1_XX_X/libs/python/src/converter/builtin_converters.cpp를 수정 (Line 38 ~ 47)

Before

  // An lvalue conversion function which extracts a char const* from a
  // Python String.
  #if PY_VERSION_HEX < 0x03000000
    void* convert_to_cstring(PyObject* obj)
    {
        return PyString_Check(obj) ? PyString_AsString(obj) : 0;
    }
  #else
    void* convert_to_cstring(PyObject* obj)
    {
        return PyUnicode_Check(obj) ? _PyUnicode_AsString(obj) : 0;
    }

After

  // An lvalue conversion function which extracts a char const* from a
  // Python String.
  #if PY_VERSION_HEX < 0x03000000
    void* convert_to_cstring(PyObject* obj)
    {
        return PyString_Check(obj) ? PyString_AsString(obj) : 0;
    }
  #elif PY_VERSION_HEX < 0x03070000
    void* convert_to_cstring(PyObject* obj)
    {
        return PyUnicode_Check(obj) ? _PyUnicode_AsString(obj) : 0;
    }
  #else
    void* convert_to_cstring(PyObject* obj)
    {
        return PyUnicode_Check(obj) ? const_cast<void*>(reinterpret_cast<const void*>(_PyUnicode_AsString(obj))) : 0;
    }
  #endif