rpcgen adds _svc extension - c

Question

Creating a simple server-client program using rpcgen.
I'm writing this .x file:
program REMOTE_PROG {
version MSG_RCV {
int STRLEN(string) = 1;
double SQUARE(double *) = 2;
int NUM_OF_DEV(int *) = 3;
} = 1;
} = 99;
executing with rpcgen file.x -> generates file_svc.c.
in the file_svc.c file, for some reason, it generates each function case with _svc extension:
case STRLEN:
xdr_argument = xdr_wrapstring;
xdr_result = xdr_int;
local = (char *(*)()) strlen_1_svc; //<--_SVC
break;
and when I try to compile the server after implementing the functions
int * strlen_1(char **, CLIENT *);
the compiler raises that error:
"_strlen_1_svc", referenced from:
_remote_prog_1 in file_svc-8501b7.o
ld: symbol(s) not found for architecture x86_64
But if I'll delete that auto generated _svc extension,local = (char *(*)()) strlen_1; //no _svc the program will compile successfully.
Why does this happen? why does the rpcgen adds the _svc extension to the functions and am I doing something wrong when I delete the _svc?
P.S same error also for square and num_of_dev functions, gave only strlen for example.
Thanks!

Answer 1

That's the convention, the _svc is short for service.
Your server needs to implement the service function, that is the strlen_1_svc function.
Your client calls the strlen_1 function. rpcgen + the RPC library does all the inbetween - it generates code for strlen_1 used by the client which will serialize the data and transfer it to the server, where an event loop dispatches the call to your code in the strlen_1_svc function.

Answer 2

After execution of rpcgen ex7.x you should have created the client and server stubs ex7_clnt.c and ex7_svc.c and also a header file ex7.h
In the header file you will have declared both functions strlen_1 and strlen_1_svc, they have to have different names as they are different functions: first one is on the client side and invokes the second one on the server side through RPC call.