Trying to find the filename for a GLSL shader texture using C++

[Anonymous]

I'm using Maya 2018 and VS and have succeeded in retrieving the name of my GLSL shader using code.

The next thing I need to achieve is to get the filename of the various shader texture files that I am using.  I want to export these for example to a text file.  The problem so far is that despite looking at code samples on the web and the poywriter plugin example I still can't get the actual texture file names.

I was able to get some plug names:

GLSLShader1.u_DiffuseEnvTexture
GLSLShader1.u_SpecularEnvTexture
GLSLShader1.u_brdfTexture
GLSLShader1.u_BaseColorTexture
GLSLShader1.u_MetallicTexture
GLSLShader1.u_RoughnessTexture
GLSLShader1.u_OcclusionTexture
GLSLShader1.u_NormalTexture
GLSLShader1.outColor
GLSLShader1.message

 However that is as far as I can get so far.

Any tips or code samples?

Thanks