int QP_ipc_prepare(command, arg1, ..., argn)
         int command;

This function sends a request to the Prolog process to evaluate a goal. The command is identified by command, which must have been obtained by an earlier call to QP_ipc_lookup(). The arguments are the values to be sent to the command, that is those in the interface specification with a + annotation. They must be in left-to-right order as they appear in the specification. They must be of the corresponding types as indicated in the specification:

             +integer:       int
             +float:         float
             +atom:          QP_atom
             +string:        char *

See the example below in ipc-rpc-cpp-exa.

On successful completion, this routine returns 0. If an error has occurred, it returns -1.