added a check for a running instance of the program

main_windows.go

@@ -12,15 +12,37 @@ BOOL SetPriority(DWORD pid, int priority) {
 */
 import "C"
 import (
+	"github.com/postfinance/single"
 	"github.com/shirou/gopsutil/process"
 	"os"
 	"runtime"
+	"syscall"
 	"time"
+	"unsafe"
 )
 
+func MessageBox(lpText string, lpCaption string, uType int) int {
+	var convertedCaption, _ = syscall.UTF16PtrFromString(lpCaption)
+	var convertedTitle, _ = syscall.UTF16PtrFromString(lpText)
+	returnCode, _, _ := syscall.NewLazyDLL("user32.dll").NewProc("MessageBoxW").Call(
+		uintptr(0),
+		uintptr(unsafe.Pointer(convertedCaption)),
+		uintptr(unsafe.Pointer(convertedTitle)),
+		uintptr(uType),
+	)
+	return int(returnCode)
+}
+
+var lockFile, _ = single.New("autoPriority")
+
 func main() {
+	if err := lockFile.Lock(); err != nil {
+		MessageBox("The program is already running", "Only one instance of the program can be run\nYou can close it via the Task Manager", 48)
+		os.Exit(1)
+	}
+
 	C.SetPriority(C.DWORD(os.Getpid()), 0x00000040)
-	for {
+	for range time.Tick(time.Minute) {
 		processes, _ := process.Processes()
 		for _, proc := range processes {
 			memoryInfo, err := proc.MemoryInfo()
@@ -29,6 +51,5 @@ func main() {
 			}
 		}
 		runtime.GC()
-		time.Sleep(time.Minute)
 	}
 }