CODEWITHSUNDEEP
functiongo
jjs
jjs

Reputation: 115

How to access private functions of another package in Golang?

I want to access a private function of a package called "pastry". But it generates error as: invalid reference to unexported identifier

Specify the way by which private functions of golang are accessible in main.

Upvotes: 4

Views: 12570

Answers (4)

graywolf
graywolf

Reputation: 7480

You can use go:linkname to map functions from same/different package to some function in yours. For example like:

package main

import (
    "fmt"

    _ "net"
    _ "unsafe"
)

//go:linkname lookupStaticHost net.lookupStaticHost
func lookupStaticHost(host string) []string

func main() {
    fmt.Println(lookupStaticHost("localhost"))
}

will produce [127.0.0.1 ::1] when executed on my machine.

Upvotes: 16

Mirek Walczak
Mirek Walczak

Reputation: 31

in the package (let's say mypackage) where you have pastry function add:

var Pastry = pastry

in main package:

mypackage.Pastry()

Upvotes: 3

i.van
i.van

Reputation: 826

You can also add public proxy-function.

For example:

You have package-private function

func foo() int {
    return 42
}

You can create public function in the same package, which will call the package-private function and return it's result

func Bar() int {
    return foo()
}

Upvotes: 7

nessuno
nessuno

Reputation: 27042

Private functions are, by definition, not accessible outside the package in which they are declared.

If you need that function outside that package, you must make it public (change the function name, turning the first letter in upper case).

Eg: if you have func doSomething() rename it to func DoSomething() and use it outside the package with <package name>.DoDomething()

Upvotes: 8

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