Need help using declare_imageio_format

[MarkCallow]

I want to add a .pam reader for my project. My code is crashing in declare_imageio_format with an access violation. Here are the relevant bits of my code:

extern "C" {
  extern ImageInput* pam_input_imageio_create();
  extern const char* pam_imageio_library_version();
  extern const char** pam_input_extensions;
}

Image*
Image::CreateFromFileUsingOIIO(const _tstring& name, bool transformOETF,
                               rescale_e rescale)
{
    declare_imageio_format(std::string("pam"),
                           pam_input_imageio_create,
                           pam_input_extensions,
                           nullptr, nullptr,
                           pam_imageio_library_version());
    ...
}

I've been unable to build a debug version of oiio to help me debug, for reasons I'll describe later. I do have the debug variant of the MacPorts openimageio port installed and active but for some reason Xcode won't let me step into the function.

Is there anything that jumps out as incorrect in the code above? Is there some library initialization function I need to call before declare_imageio_format?

Issues with making a debug library

Until now I have been using the library installed by MacPorts which is v2.1.17.0.

I successfully built a library from current master. However I need the public header files. There is no target to build them so I tried to build the package. but I got errors. I then checked out tag release-2.0.17.0 removed the build directory and redid the cmake config. However I am getting errors about "no template named make_unique" and "auto return without a trailing return type ... is a C++14 extension". So I have given up.

[MarkCallow]

I've figured out what is going on. In my Pam plug-in I have

OIIO_EXPORT const char* pam_input_extensions[] = { "pam", nullptr };

If I change the extern declaration to

const char* pam_input_extensions[];

then the function no longer crashes. It appears that with the original declaration, the assigmnent

const char** foo = pam_input_extensions;

ends up with foo being set to the address of the string at pam_input_extensions[0] so *foo is a bogua address. I don't fully understand why.