---
name: "Tk_MainWindow"
section: "3tk"
platform: "linux"
package: "tk8.6-doc"
version: "8.6.16-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Tk_MainWindow/3tk"
---

# Tk\_MainWindow(3tk)

functions for querying main window information

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```

## NAME

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

## SYNOPSIS

```
#include <tk.h>

Tk_Window
Tk_MainWindow(interp)

int
Tk_GetNumMainWindows()
```

## ARGUMENTS

- Tcl\_Interp *\*interp* (in/out)

  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 interpreter *interp*'s result.

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

## KEYWORDS

application, main window