how to turn char ** into []string in Go

doublearray.go

package main

import (
	"errors"
	"fmt"
	"log"
	"reflect"
	"unsafe"
)

/*
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char** getDoubleArray(int *size) {
    int i;
    char buff[1024];

    *size = 'z' - 'a' + 1;
    char **list = (char **)malloc(*size * sizeof(char *));

    if (NULL == list) {
        *size = 0;
        return NULL;
    }

    for (i = 0; i < *size; i++) {
        sprintf(buff, "%c [0x%02X]", 'a' + i, 'a' + i);
        list[i] = strdup(buff);
    }

    return list;
}
*/
import "C"

func main() {
	var size C.int
	ptr := unsafe.Pointer(C.getDoubleArray(&size))

	lines, err := StringArrayList(ptr, int(size))

	if err != nil {
		log.Fatal(err)
	}

	for _, line := range lines {
		fmt.Println(line)
	}
}

func StringArrayList(ptr unsafe.Pointer, size int) ([]string, error) {

	if nil == ptr || 0 == size {
		return nil, errors.New("params error")
	}

	var slice []*C.char
	header := (*reflect.SliceHeader)((unsafe.Pointer(&slice)))
	header.Cap = size
	header.Len = size
	header.Data = uintptr(unsafe.Pointer(ptr))

	ret := make([]string, size)
	for i := 0; i < size; i++ {
		verb := C.GoString(slice[i])
		C.free(unsafe.Pointer(slice[i])) // free if needed
		ret[i] = verb
	}

	C.free(ptr) // free if needed
	return ret, nil
}