Structures and pointers question

If I have the structure below:

Code:

     10 struct
     11      {
     12         int cin;
     13         int mo;
     14         int next_step;
     15         int tested_cin;
     16      } coil_info;

and in SQL declare it states:

Code:

     335         EXEC SQL BEGIN DECLARE SECTION;
     336          coil_info coil;
     337         EXEC SQL END DECLARE SECTION;

when (&coil) and (coil) is passed to functions like below what is the difference between the two?

update_coil(coil)
then using coil->cin

update_coil(&coil)
then using coil->cin

The two would have the same value correct?

One passed address of pointer and other address of the actual data? I see no difference. Any help is appreciated.

coil IS the struct, while &coil is its address. coil is not in any way, shape, or form an address. coil->cin should not compile.

update_coil(coil)
then using coil->cin

You only pass a copy of the object coil: the value of cin after the call is still
the same value than before the call.

update_coil(&coil)
then using coil->cin

This time you pass the object itself (through its address) so the function
can modify its content: cin contains the updated value after the call.