windows-specific extensions for accessing Windows profileapi

src/libstd/sys/windows/ext/mod.rs

@@ -16,6 +16,7 @@ pub mod io;
 pub mod process;
 pub mod raw;
 pub mod thread;
+pub mod time;
 
 /// A prelude for conveniently writing platform-specific code.
 ///

src/libstd/sys/windows/ext/time.rs

@@ -0,0 +1,21 @@
+//! Windows-specific extensions to access Windows profileapi.
+
+#![stable(feature = "windows_profileapi", since = "1.43.0")]
+
+use crate::sys::c;
+use crate::sys::cvt;
+
+/// Stores the current value of the performance counter to the memory pointed by the argument pointer,
+/// Counter value is a high resolution (<1us) time stamp that can be used for time-interval measurements.
+#[stable(feature = "windows_profileapi", since = "1.43.0")]
+pub fn QueryPerformanceCounter(qpc_value: &mut i64) -> crate::io::Result<i32> {
+    cvt(unsafe { c::QueryPerformanceCounter(qpc_value) })
+}
+
+/// Stores the frequency of the performance counter to the memory pointed by the argument pointer.
+/// The frequency of the performance counter is fixed at system boot and is consistent across all processors.
+/// Therefore, the frequency need only be queried upon application initialization, and the result can be cached.
+#[stable(feature = "windows_profileapi", since = "1.43.0")]
+pub fn QueryPerformanceFrequency(frequency: &mut i64) -> crate::io::Result<i32> {
+    cvt(unsafe { c::QueryPerformanceFrequency(frequency) })
+}