call goroslib service on C client will block

[sniperZj]

@aler9 hello
The call function of the service called by the client written in C returns boolean type. If I use goroslib to provide a service to retrieve the database and return a record, if no record is found, the call function of the C client will be blocked.

[aler9]

Hello,
Service providers return two different values when receiving a request: one is the response, the other one is a boolean flag. If you want to interact with the add_two_ints example client, you can do it in this way:

package main

import (
	"github.com/aler9/goroslib"
	"github.com/aler9/goroslib/pkg/msg"
)

// define a custom service.
// unlike the standard library, a .srv file is not needed.

type AddTwoIntsReq struct {
	A int64
	B int64
}

type AddTwoIntsRes struct {
	Sum int64
}

type AddTwoInts struct {
	msg.Package `ros:"my_package"`
	AddTwoIntsReq
	AddTwoIntsRes
}

func onService(req *AddTwoIntsReq) (*AddTwoIntsRes, bool) {
	return &AddTwoIntsRes{
		Sum: req.A + req.B,
	}, true
}

func main() {
	// create a node and connect to the master
	n, err := goroslib.NewNode(goroslib.NodeConf{
		Name:          "goroslib_sp",
		MasterAddress: "127.0.0.1:11311",
	})
	if err != nil {
		panic(err)
	}
	defer n.Close()

	// create a service provider
	sp, err := goroslib.NewServiceProvider(goroslib.ServiceProviderConf{
		Node:     n,
		Name:     "add_two_ints",
		Srv:      &AddTwoInts{},
		Callback: onService,
	})
	if err != nil {
		panic(err)
	}
	defer sp.Close()

	// freeze main loop
	select {}
}

[sniperZj]

@aler9 good