CODEWITHSUNDEEP
gocgo
dingrui
dingrui

Reputation: 507

Cannot get environment value

When I use setenv to set an environment value, it cannot be got by os.Getenv. Can someone tell me why?

package main
/*
#include <stdlib.h>
#include <stdio.h>
*/
import "C"

import "os"
import "strings"
import "fmt"

func main()  {
    C.setenv(C.CString("CSET"), C.CString("1.1.1.1:1111"), C.int(1)) //call setenv 
    C.puts(C.getenv(C.CString("CSET")))  // call getenv

    addrs := strings.Split(os.Getenv("CSET"), ";")
    fmt.Printf("addrs = %v\n", addrs)

    os.Setenv("GOSET", "2.2.2.2:2222")
    C.puts(C.getenv(C.CString("GOSET")))
}

dingrui@dingrui-PC:~/Projects/Temp$ go run env.go 
1.1.1.1:1111
addrs = []
2.2.2.2:2222

Upvotes: 0

Views: 260

Answers (1)

chmike
chmike

Reputation: 22154

This is a feature of Getenv.

In the source file syscall/env_unix.go, we see that a copy of the environment variables is made in the program initialization phase (envs []string = runtime_envs()).

This copy is not updated if you modify the program environment variables in the background using the C functions.

Unfortunately, there is no way around this feature.

Upvotes: 1

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