从Python调用Go时出现“无效内存地址”

Question

我正在尝试扩展Calling Go Functions from Other Languages中的代码。我想看看如何处理返回错误的函数。请参阅下面的代码，我在运行Python代码时得到panic: runtime error: invalid memory address or nil pointer dereference。有没有办法解决这个问题？你知道吗

gmath.go公司

package main

import (
    "fmt"
)

import "C"

//export Div
func Div(x, y float64) (float64, error) {
    fmt.Printf("Div called: x=%f, y=%f\n", x, y)
    if y == 0 {
        return 0, fmt.Errorf("ZeroDivisionError")
    }
    return x / y, nil
}

func main() {}

gmath.py公司

import ctypes


class GoInterface(ctypes.Structure):
    _fields_ = [
        ('t', ctypes.c_void_p),
        ('v', ctypes.c_void_p),
    ]


class DivRet(ctypes.Structure):
    _fields_ = [
        ('result', ctypes.c_float),
        ('error', GoInterface),
    ]


lib = ctypes.cdll.LoadLibrary('./gmath.so')
lib.Div.argtypes = [ctypes.c_double, ctypes.c_double]
lib.Div.restype = DivRet

r = lib.Div(1.2, 2.3)

示例运行

$ make
go build -o gmath.so -buildmode=c-shared gmath.go
$ python gmath.py
Div called: x=1.200000, y=2.300000
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x17 pc=0x7fbe5fda928d]

goroutine 17 [running, locked to thread]:
main._cgoexpwrap_448ea9090bef_Div.func1(0xc42003cea8)
    command-line-arguments/_obj/_cgo_gotypes.go:46 +0x42
main._cgoexpwrap_448ea9090bef_Div(0x3ff3333333333333, 0x4002666666666666, 0x3fe0b21642c8590b, 0x0, 0x0)
    command-line-arguments/_obj/_cgo_gotypes.go:48 +0xaa
[1]    29009 abort (core dumped)  python gmath.py

Answer 1

结果的错误部分似乎是最初的问题。如果我将error改为字符串并返回（float64，*C.char），它就可以工作了。你知道吗