如何使用Windows DLL方法

Question

I am trying to use the GetPhysicallyInstalledSystemMemory method which is present in kernel32.dll.

It requires a single argument of the type PULONGLONG, but I have no idea how to map this into a golang variable. Here is my current attempt which results in "err: The parameter is incorrect".

Can anyone explain how to do this?

package main

import (
    "fmt"
    "syscall"
)

var memory uintptr

func main() {
    kernel32 := syscall.NewLazyDLL("kernel32.dll")
    getPhysicallyInstalledSystemMemoryProc := kernel32.NewProc("GetPhysicallyInstalledSystemMemory")

    ret, _, err := getPhysicallyInstalledSystemMemoryProc.Call(uintptr(memory))
    fmt.Printf("GetPhysicallyInstalledSystemMemory, return: %+v
", ret)
    fmt.Printf("GetPhysicallyInstalledSystemMemory, memory: %d
", memory)
    fmt.Printf("GetPhysicallyInstalledSystemMemory, err: %s
", err)

}

Answer 1

1. The PULONGLONG parameter type translates to *uint64
2. You must cast the the address of the memory variable to the unsafe.Pointer type and then to uintptr

package main

import (
    "fmt"
    "syscall"
    "unsafe"
)

func main() {
    kernel32 := syscall.NewLazyDLL("kernel32.dll")
    getPhysicallyInstalledSystemMemoryProc := kernel32.NewProc("GetPhysicallyInstalledSystemMemory")

    var memory uint64

    ret, _, err := getPhysicallyInstalledSystemMemoryProc.Call(uintptr(unsafe.Pointer(&memory)))
    fmt.Printf("GetPhysicallyInstalledSystemMemory, return: %+v
", ret)
    fmt.Printf("GetPhysicallyInstalledSystemMemory, memory: %d
", memory)
    fmt.Printf("GetPhysicallyInstalledSystemMemory, err: %s
", err)

}