Simple Lua binding for QueryPerformanceCounter function from WinAPI. Returns a function, not a table.

lqueryperformancecounter.c

#include "lua.h"
#include <windows.h>

static LARGE_INTEGER pc, pf;

static int queryperformancecounter(lua_State* L) {
    QueryPerformanceCounter(&pc);
    lua_pushnumber(L, (double)pc.QuadPart / pf.QuadPart);
    return 1;
}

int luaopen_queryperformancecounter(lua_State* L) {
    QueryPerformanceFrequency(&pf);
    lua_pushcfunction(L, queryperformancecounter);
    return 1;
}

// Compile with:
//  gcc -O2 -shared -fPIC -o queryperformancecounter.dll lqueryperformancecounter.c <path/to/lua>/bin/lua54.dll -I<path/to/lua>/include
// Usage:
//  local qpc = require 'queryperformancecounter'
//  local t = qpc()
//  print(qpc() - t)