gotk4

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First of all: This project is nice work!

But while I'm playing with gotk4, I realized, that memory is not freed after a window or a application is closed/destroyed or finished:

package main

import (
	"log"
	"os"
	"runtime"
	"runtime/debug"
	"time"

	"github.com/diamondburned/gotk4/pkg/gio/v2"
	"github.com/diamondburned/gotk4/pkg/gtk/v4"
)

func main() {
	time.Sleep(time.Second * 5)
	stats := &runtime.MemStats{}
	debug.FreeOSMemory()
	runtime.ReadMemStats(stats)
	log.Printf("%vKB\n", stats.Sys/1024)

	app := gtk.NewApplication("com.github.diamondburned.gotk4-examples.gtk4.simple", gio.ApplicationFlagsNone)
	app.ConnectActivate(func() {
		window1 := gtk.NewApplicationWindow(app)
		window1.SetTitle("gotk4 Example #1")
		window1.SetChild(gtk.NewLabel("Hello from Go!"))
		window1.SetDefaultSize(400, 300)
		window1.Show()
		window2 := gtk.NewApplicationWindow(app)
		window2.SetTitle("gotk4 Example #2")
		window2.SetChild(gtk.NewLabel("Hello from Go!"))
		window2.SetDefaultSize(400, 300)
		window2.Show()
		window3 := gtk.NewApplicationWindow(app)
		window3.SetTitle("gotk4 Example #3")
		window3.SetChild(gtk.NewLabel("Hello from Go!"))
		window3.SetDefaultSize(400, 300)
		window3.Show()
		go func() {
			stats := &runtime.MemStats{}
			debug.FreeOSMemory()
			runtime.ReadMemStats(stats)
			log.Printf("%vKB\n", stats.Sys/1024)

			time.Sleep(time.Second * 5)
			window1.Close()
			window1.Destroy()
			stats = &runtime.MemStats{}
			debug.FreeOSMemory()
			runtime.ReadMemStats(stats)
			log.Printf("%vKB\n", stats.Sys/1024)

			time.Sleep(time.Second * 5)
			window2.Close()
			window2.Destroy()
			stats = &runtime.MemStats{}
			debug.FreeOSMemory()
			runtime.ReadMemStats(stats)
			log.Printf("%vKB\n", stats.Sys/1024)

			time.Sleep(time.Second * 5)
			window3.Close()
			window3.Destroy()
			stats = &runtime.MemStats{}
			debug.FreeOSMemory()
			runtime.ReadMemStats(stats)
			log.Printf("%vKB\n", stats.Sys/1024)
		}()
	})

	if code := app.Run(os.Args); code > 0 {
		os.Exit(code)
	}

	stats = &runtime.MemStats{}
	debug.FreeOSMemory()
	runtime.ReadMemStats(stats)
	log.Printf("%vKB\n", stats.Sys/1024)
}

This prints:

2023/04/14 19:47:22 13373KB
2023/04/14 19:47:22 13437KB
2023/04/14 19:47:27 13693KB
2023/04/14 19:47:32 13693KB
2023/04/14 19:47:37 13693KB
2023/04/14 19:47:37 13693KB

Any suggestion what I'm doing wrong?

I'm not too sure myself, but the windows might only be freed after several GC cycles. It might be better to run the GC every second or so in a background goroutine and monitor memory usage that way.