How do I use the gwoapi10.h file?

I was given a download which has zero relevant README.txt.
the only file worth mentioning is gwoapi10.h which is a c header file.
there is no main.cpp which is required for execution (I program in c ).
It appears to have the functions I need but I am missing a significant part, the main{}
Where is the .exe or .o that I am supposed to execute this file against?