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

# Tk\_Main(3)

main program for Tk-based applications

## NAME

Tk\_Main - main program for Tk-based applications

## SYNOPSIS

```
#include <tk.h>

Tk_Main(argc, argv, appInitProc)
```

## ARGUMENTS

Number of elements in *argv*. Array of strings containing command-line arguments. Address of an application-specific initialization procedure. The value for this argument is usually **Tcl\_AppInit**.

## DESCRIPTION

**Tk\_Main** acts as the main program for most Tk-based applications. Starting with Tk 4.0 it is not called **main** anymore because it  is part of the Tk library and having a function **main** in a library (particularly a shared library) causes problems on many systems. Having **main** in the Tk library would also make it hard to use Tk in C++ programs, since C++ programs must have special C++ **main** functions.

Normally each application contains a small **main** function that does nothing but invoke **Tk\_Main**. **Tk\_Main** then does all the work of creating and running a **wish**-like application.

When it is has finished its own initialization, but before it processes commands, **Tk\_Main** calls the procedure given by the *appInitProc* argument.  This procedure provides a for the application to perform its own initialization, such as defining application-specific commands.  The procedure must have an interface that matches the type **Tcl\_AppInitProc**: typedef int Tcl\_AppInitProc(Tcl\_Interp \**interp*); *AppInitProc* is almost always a pointer to **Tcl\_AppInit**; for more details on this procedure, see the documentation for **Tcl\_AppInit**.

## KEYWORDS

application-specific initialization, command-line arguments, main program