---
name: "MainWin"
section: "3"
platform: "macos"
package: "tcl"
version: "152"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/MainWin/3"
---

# MainWin(3)

functions for querying main window information

## NAME

Tk\_MainWindow, Tk\_GetNumMainWindows - functions for querying main window information

## SYNOPSIS

```
#include <tk.h>

Tk_Window
Tk_MainWindow(interp)

int
Tk_GetNumMainWindows()
```

## ARGUMENTS

Interpreter associated with the application.

## DESCRIPTION

A main window is a special kind of toplevel window used as the outermost window in an application.

If *interp* is associated with a Tk application then **Tk\_MainWindow** returns the application's main window. If there is no Tk application associated with *interp* then **Tk\_MainWindow** returns NULL and leaves an error message in *interp-\>result*.

**Tk\_GetNumMainWindows** returns a count of the number of main windows currently open in the process.

## KEYWORDS

application, main window