Using Structs Defined In Native Plugin

I am currently creating a Unity native plugin for the pocketsphinx library (CMU Sphinx Downloads – CMUSphinx Open Source Speech Recognition). I have read all the official documentation relating to Unity plugins.

My question is, how do I use structs defined by the library? Right now, I have a couple DLLs that encompass all of the pocketsphinx library, and I am trying to import all of the available functions into a C# script. However, many of these functions require structs defined by the library as argument, eg. in pocketsphinx.h

POCKETSPHINX_EXPORT
ps_decoder_t *ps_init(cmd_ln_t *config);

where the type cmd_ln_t is a struct defined in cmd_ln.h

How can I import and use this function properly in Unity? Also, I am trying to make this cross-platform, so will I be running into similar issues in Android, iOS, and Unix?

Further research on the topic shows that this is impossible:
http://stackoverflow.com/questions/315051/using-a-class-defined-in-a-c-dll-in-c-sharp-code

I’ll look deeper into whether the approach described in the above link can apply to my project.