Add fallback impl for GetSystemTimeAsFileTime

(only used for NT 3.1)

Author: seritools

library/std/src/sys/windows/c.rs

@@ -199,6 +199,20 @@ if #[cfg(not(target_vendor = "uwp"))] {
 }
 }
 
+#[repr(C)]
+pub struct SYSTEMTIME {
+    wYear: WORD,
+    wMonth: WORD,
+    wDayOfWeek: WORD,
+    wDay: WORD,
+    wHour: WORD,
+    wMinute: WORD,
+    wSecond: WORD,
+    wMilliseconds: WORD,
+}
+
+pub type LPSYSTEMTIME = *mut SYSTEMTIME;
+
 pub unsafe extern "system" fn WriteFileEx(
     hFile: BorrowedHandle<'_>,
     lpBuffer: *mut ::core::ffi::c_void,
@@ -407,6 +421,15 @@ compat_fn_with_fallback! {
     pub fn GetProcessId(handle: HANDLE) -> DWORD {
         rtabort!("unavailable")
     }
+
+    // >= 95 / NT 3.5
+    // https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime
+    pub fn GetSystemTimeAsFileTime(lpSystemTimeAsFileTime: LPFILETIME) -> () {
+        // implementation based on old MSDN docs
+        let mut st: SYSTEMTIME = crate::mem::zeroed();
+        GetSystemTime(&mut st);
+        crate::sys::cvt(SystemTimeToFileTime(&st, lpSystemTimeAsFileTime)).unwrap();
+    }
 }
 
 compat_fn_optional! {
@@ -469,4 +492,7 @@ extern "system" {
     ) -> HANDLE;
 
     pub fn PulseEvent(hEvent: HANDLE) -> BOOL;
+
+    pub fn GetSystemTime(lpSystemTime: LPSYSTEMTIME);
+    pub fn SystemTimeToFileTime(lpSystemTime: *const SYSTEMTIME, lpFileTime: LPFILETIME) -> BOOL;
 }