为什么在我运行代码后，出现undefined：returnAllSMSBlasts，所以我的函数不起作用为什么？

I Make Restful api , I want display result , but golang say error about function , error say "undefined: returnAllSMSBlasts" why , can you check my code error ?

this my code

data.go

package main

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

func returnAllSMSBlasts(w http.ResponseWriter, r *http.Request)  {
    var smsblasts SMSBlasts
    var arr_smsblast []SMSBlasts
    var response Response

    db := connect()
    defer db.Close()

    rows, err := db.Query("Select SequenceID,MobilePhone,Output,WillBeSentDate,SentDate,Status,DtmUpd")
    if err != nil{
        log.Print(err)
    }

    for rows.Next(){
        if err := rows.Scan(&smsblasts.SequenceID, &smsblasts.MobilePhone,
            &smsblasts.Output, &smsblasts.WillBeSentDate,
            &smsblasts.SentDate, &smsblasts.Status,
            &smsblasts.DtmUpd); err != nil{
                log.Fatal(err.Error())
        }else{
            arr_smsblast = append(arr_smsblast , smsblasts)
        }
        }
    response.Status = 1
    response.Message = "success"
    response.Data = arr_smsblast

    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(response)
}

and this my code

main.go

    package main

    import (
    "fmt"
    "log"
    "net/http"
    "github.com/gorilla/mux"
    _ "github.com/denisenkom/go-mssqldb"
)


    func main() {

        router := mux.NewRouter()
        router.HandleFunc("/postsmsblasts", returnAllSMSBlasts).Methods("POST")
        http.Handle("/", router)
        fmt.Println("Connected to port 1234")
        log.Fatal(http.ListenAndServe(":1234", router))

    }