title: Convert C file pointer address into Integer
body: <p>I have a C file pointer which I must pass to a Fortran77 program (as an integer) only to be used back again in the C program (as a file pointer) for writing more data into a text file. My C skills are outdated since I have forgotten most of it. Can anyone tell me how to convert a C FILE pointer into an integer and back? I would appreciate your help.</p>
  
  <p>I am maintaining a legacy code that just worked fine (by accident) a 10 year old compiler. I am having problems porting the code. The new compilers are the intel C and Fortran  compilers.</p>
  
  <p>I know Fortran 2003 provides ISO bindings for C but I cannot use them here for other reasons.</p>