Getsystemtimepreciseasfiletime Windows 7 Upd May 2026
| Environment | Typical Precision | |-------------|-------------------| | Default Windows 7 (no update) | ~10–16 ms | | Windows 7 + KB2670838 | ~0.5 – 1 μs (microsecond) | | Windows 10/11 | ~0.1 – 1 μs |
int main() HMODULE hKernel = GetModuleHandle(L"kernel32.dll"); GetSystemTimePreciseAsFileTimePtr pGetTimePrecise = (GetSystemTimePreciseAsFileTimePtr) GetProcAddress(hKernel, "GetSystemTimePreciseAsFileTime"); getsystemtimepreciseasfiletime windows 7 upd
GetSystemTimePreciseAsFileTime is a Win32 API function defined in sysinfoapi.h . Its signature is: In practice, you can expect on most modern
return 0; C# cannot directly call this API without P/Invoke, but you can use: but you can use: [DllImport("kernel32.dll"
[DllImport("kernel32.dll", SetLastError = true)] static extern void GetSystemTimePreciseAsFileTime(out long lpSystemTimeAsFileTime); Again, check for missing entry point exceptions and fall back to DateTime.UtcNow (which internally uses GetSystemTimeAsFileTime ). Even with GetSystemTimePreciseAsFileTime , precision depends on hardware and system configuration:
The back-ported version relies on the same KeQueryPerformanceCounter internal mechanism but wrapped in FILETIME format. In practice, you can expect on most modern hardware running the update. Common Issues and Troubleshooting 1. Missing Update Error (error 127) Symptom: GetProcAddress returns NULL or “The specified procedure could not be found.”