Functions as parameters in C -

i'm working on project intro c class, creating hash table implementation in c current question pertains how function written in code skeleton provided professor. here header definition of create method:

     table* create(long (*hash)(void* key),           bool (*equals)(void* key1, void* key2),           void (*print)(void* key1, void* key2)); 

this appears pointers functions parameters? i'm not sure how call this, or happens when called. i'm not sure these methods (hash, equals, , print) coming from. appreciated. thanks

this appears pointers functions parameters?

yes.

i'm not sure how call this

to invoke function create, pass addresses of functions right types call create:

create(&f1, &f2, &f3); 

or happens when called.

any place in body of create where(*) pointed function invoked, actual function (for instance f1) ends being called provided arguments. (*equals)(k1, k2); fictional example have occurred inside create.

(*) or, in case, function function pointers struct allocated create have stored them

---

in fact c allows write create(f1, f2, f3); in first case , equals(k1, k2); in second, that's convenience.