我確信我遺漏了一些簡單的基本問題，我是新手。假設(shè)我不想使用默認(rèn)記錄器，如何設(shè)置記錄器以便它可以在函數(shù)之間共享？logissue.gopackage mainimport ( "fmt" "github.com/pkg/errors" "log" "os")var dlog log.Loggerconst logfile string = "killer.log"const logprefix string = "LOGTEST: "func setupLogger(filename, prefix string) (*log.Logger, error) { out, err := os.OpenFile(filename, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644) if err != nil { return nil, errors.Wrap(err, "can't open logfile for writing") } return log.New(out, prefix, log.LstdFlags), nil}func uselog() error { fmt.Printf("%T\n", dlog) dlog.Printf("Hello") ///// < Here is the issue return nil}func main() { dlog, err := setupLogger(logfile, logprefix) if err != nil { fmt.Printf("%+v", err) } dlog.Printf("test from main") uselog()}stdoutlog.Loggerpanic: runtime error: invalid memory address or nil pointer dereference[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x10970b8]goroutine 1 [running]:log.(*Logger).Output(0x116dd00, 0x2, 0xc000016106, 0x5, 0x0, 0x0) /usr/local/go/src/log/log.go:172 +0x1e8log.(*Logger).Printf(0x116dd00, 0x10c9202, 0x5, 0x0, 0x0, 0x0) /usr/local/go/src/log/log.go:179 +0x7emain.uselog(0xc000088050, 0x10ca43b) /Users/sequoia/learning/Ex_Files_Go_EssT/Exercise Files/logissue.go:25 +0xc4main.main() /Users/sequoia/learning/Ex_Files_Go_EssT/Exercise Files/logissue.go:35 +0xeeexit status 2killer.logLOGTEST: 2019/02/17 18:25:12 test from main
2 回答
慕尼黑的夜晚無繁華
TA貢獻(xiàn)1864條經(jīng)驗(yàn) 獲得超6個(gè)贊
因此，首先，根據(jù)您上面的代碼，您嘗試設(shè)置一個(gè)帶有指針記錄器的非指針記錄器，但該指針記錄器不起作用。其次，您在設(shè)置 dlog 時(shí)使用 := ，它在您的 main 方法中創(chuàng)建一個(gè)作用域變量，而不是設(shè)置您的全局變量
江戶川亂折騰
TA貢獻(xiàn)1851條經(jīng)驗(yàn) 獲得超5個(gè)贊
我試過這個(gè)：
import (
"fmt"
"github.com/pkg/errors"
"log"
"os"
)
const logfile string = "killer.log"
const logprefix string = "LOGTEST: "
var DLog *log.Logger
func setupLogger(filename, prefix string) {
var err error
out, err := os.OpenFile(filename, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
log.Fatal( nil, errors.Wrap(err, "can't open logfile for writing"))
}
DLog=log.New(out, prefix, log.LstdFlags)
fmt.Println("Log object: ",DLog)
}
func uselog() error {
DLog.Print("Hello") ///// < Here is the issue
DLog.Print("I have something standard to say")
fmt.Println("I am done")
return nil
}
func main() {
setupLogger(logfile, logprefix)
DLog.Printf("test from main")
uselog()
}
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