cgo不会在导入的包中导出函数 [英] cgo doesn't export functions in imported packages

问题描述

我正在尝试使用 CGO 将现有的Go程序包构建到C共享库和标头中.

I'm trying to build existed Go package into C shared library and header using CGO.

我使用记录的 -buildmode c-shared 构建了程序包.

I built the package with -buildmode c-shared as documented.

-buildmode=c-shared
    Build the listed main package, plus all packages it imports,
    into a C shared library. The only callable symbols will
    be those functions exported using a cgo //export comment.
    Requires exactly one main package to be listed

并使用//export Func 将函数公开为C符号.

And used //export Func to expose functions as C symbols.

main 包中的所有//export 函数均已正确导出.但是，当我将这些功能移到子包(带有//export )时，这些功能不会导出.我也将子包导入了 main 包中.

All //export functions in main package are exported properly. However when I moved those functions to sub-package (with //export), those functions are not exported. I imported the sub-package in main package, too.

这是我的代码.

main.go

package main

import "C"

import (
    "fmt"
    _ "github.com/onosolutions/archanan-cgo/c"
    "math/rand"
)

// FuncInMain generates a random integer.
//export FuncInMain
func FuncInMain(max C.int) C.int {
    return C.int(rand.Intn(int(max)))
}

func main() {
    fmt.Printf("Hello World %d!\n", int(FuncInMain(256)))
}

c/c.go

package c

import "C"

import (
    "math/rand"
)

// FuncInSubPackage generates a random integer.
//export FuncInSubPackage
func FuncInSubPackage(max C.int) C.int {
    return C.int(rand.Intn(int(max)))
}

然后仅导出 FuncInMain .

我通读了 CGO文档，但是关于分包导出没有什么可说的.我获得的唯一线索是通过 go help buildmode ，但是它表示所有导入的子包都将被编译.我不确定是否不支持它，或者我错过了一些配置.

I read through CGO documentation, but there's nothing saying about exporting in sub-packages. The only clue I got is through go help buildmode, but it said that all imported sub-packages will be compiled. I'm not sure whether it isn't supported or I missed some configurations.

我很想实现这一点，以便能够对//export 函数进行模块化.

I'd love to achieve that to be able to modularize //export functions.

推荐答案

他们两个都有自己的 C.type ，据我所知，无法通过导入函数C.type ，但使用链接.

Both of them have own C.type, so as far as I know, there's no way to import function with C.type but using linking.

我没有尝试过，但是给了机会:

I didn't tried, but give it a chance:

import _ "unsafe"

//go:linkname FuncInSubPackage c.FuncInSubPackage
//export FuncInSubPackage
func FuncInSubPackage(max C.int) C.int

这篇关于cgo不会在导入的包中导出函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！