我正在尝试转换C++ COM 代码 https://technet.microsoft.com/pt-br/aa382113(v=vs.71) for TaskScheduler
Rust 并坚持VARIANT
的论证ITaskService::Connect
:
extern crate winapi;
use winapi::{
ctypes::c_void,
shared::{
guiddef::{GUID, REFCLSID, REFIID},
ntdef::{HRESULT, NULL},
rpcdce::{RPC_C_AUTHN_LEVEL_PKT_PRIVACY, RPC_C_IMP_LEVEL_IMPERSONATE},
winerror::FAILED,
wtypes::VARENUM,
wtypesbase::CLSCTX_INPROC_SERVER,
},
um::{
combaseapi::{CoCreateInstance, CoInitializeEx, CoInitializeSecurity, CoUninitialize},
oaidl,
objbase::COINIT_MULTITHREADED,
taskschd::{ITaskService, TaskScheduler},
},
Class, Interface,
}; // 0.3.7
fn main() {
// Create an instance of the Task Service.
let mut p_service: *mut ITaskService = unsafe { std::mem::zeroed() };
let hr = unsafe {
CoCreateInstance(
&TaskScheduler::uuidof(),
std::ptr::null_mut(),
CLSCTX_INPROC_SERVER,
&ITaskService::uuidof(),
&mut p_service as *mut *mut ITaskService as *mut *mut c_void,
)
};
// [...]
// // Connect to the task service.
// let hr = pService->Connect(_variant_t(), _variant_t(),
// _variant_t(), _variant_t());
let hr = unsafe {
(&mut *p_service).Connect(
oaidl::VARIANT { /* VT_EMPTY HERE */ },
oaidl::VARIANT { /* VT_EMPTY HERE */ },
oaidl::VARIANT { /* VT_EMPTY HERE */ },
oaidl::VARIANT { /* VT_EMPTY HERE */ },
)
};
}
The docs https://learn.microsoft.com/en-us/cpp/cpp/variant-t-variant-t?view=vs-2019#remarks say:
_variant_t( )
构造一个空的_variant_t
目的,VT_EMPTY
.
我发现没有提及如何使用自述文件中所述的变体:
Use std::mem::zeroed()
创建联合的实例,然后使用其中一种变体方法分配所需的值。
在检查“变体”文档时,没有_variant_t
fn 在列表中,所以不确定它在 Rust 中叫什么
Errors
field `0` of struct `winapi::um::oaidl::VARIANT_n1` is private
field `0` is private
for
oaidl::VARIANT {
n1: oaidl::VARIANT_n1 {
0: [0, 0, 0]
}
}