rpc_clnt_create(3nsl): rpc_createerr is a variable, not a function
From the rpc_clnt_create(3nsl) man page:
struct rpc_createerr rpc_createerr ... These routines are MT-Safe. In the case of multithreaded applications, the -mt option must be specified on the com- mand line at compilation time. When the -mt option is specified, rpc_createerr() becomes a macro that enables each thread to have its own rpc_createerr(). See threads(5). ... rpc_createerr() A global variable whose value is set by any RPC client handle creation routine that fails. It is used by the routine clnt_pcreateerror() to print the reason for the failure.
Since rpc_createerr is a global variable, there shouldn't be parens (three times above). In addition, as a minor nit, semicolon should be placed after the rpc_createerr declaration in the man page synopsis.