package main

import (
    "encoding/json"
    "log"
    "net"
    "net/http"
    "net/http/fcgi"
    "os"
)

func main() {
    //setup the config
    configFile := "config.json"
    fd, err := os.Open(configFile)
    if err != nil {
        log.Fatalf("Can't open config file: %v", configFile)
    }
    CFG := config{}
    err = json.NewDecoder(fd).Decode(&CFG)
    if err != nil {
        log.Fatalf("parse config error: %v", err)
    }

    //init DB connection
    db.InitConnectionInfo(CFG.Database.Host, CFG.Database.Port, CFG.Database.Database, CFG.Database.Username, CFG.Database.Password)

    //register HTTP handler
    sessionHandler := &handlers.SessionHandler{}
    http.Handle("/sessions", sessionHandler)
    http.Handle("/sessions/", sessionHandler)

    userHandler := &handlers.UserHandler{
        Facebook:      &oa.OAuth{AppId: CFG.Facebook.Key, Secret: CFG.Facebook.Secret},
        Sina:          &oa.OAuth{AppId: CFG.Sina.Key, Secret: CFG.Sina.Secret},
        Google:        &oa.OAuth{AppId: CFG.Google.Key, Secret: CFG.Google.Secret},
        Tencent:       &oa.OAuth{AppId: CFG.Tencent.Key, Secret: CFG.Tencent.Secret},
        Mixpanel:      &hu.Share{Token: CFG.Mixpanel.Token},
        FacebookShare: &hu.Share{Token: CFG.Facebook.Token},
        SinaShare:     &hu.Share{Token: CFG.Sina.Token},
        GoogleShare:   &hu.Share{Token: CFG.Google.Token},
        TencentShare:  &hu.Share{Token: CFG.Tencent.Token},
    }
    http.Handle("/users", userHandler)
    http.Handle("/users/", userHandler)

    //and so on ...

    //run server
    log.Println("start listen: ", CFG.FcgiAddr)
    l, _ := net.Listen("tcp", CFG.FcgiAddr)
    log.Fatalf("server error is %v", fcgi.Serve(l, nil))
    //@@select {}
    log.Println("end listen")
}

var x = &{...} //init value
fillX(..., x) //fill the fields of x pointer
//here the fields of x pointer is not same to inner of fillX func

var x = &{...}
x = fullX(..., x)
the problem resolved.