First of all, your file should be written in binary which contains nothing but the objects of your c structure.
Here's a breakdown of what you should do:
1. Open the file in binary format and read to the end of the file. Make sure the size is correct (correct size should be a multiple of your c structure's size)
2. If the structure is correct, allocate memory to the pointer using malloc()
3. use fread() to read the whole chunk to the pointer
You're now ready to access your c structure from the pointer.