Book Image

Tcl/Tk 8.5 Programming Cookbook

Book Image

Tcl/Tk 8.5 Programming Cookbook

Overview of this book

With Tcl/Tk, you can create full-featured cross-platform applications in a simple and easy-to-understand way without any expensive development package; the only tools required are a simple text editor and your imagination. This practical cookbook will help you to efficiently interact with editors, debuggers, and shell type interactive programs using Tcl/Tk 8. This cookbook will comprehensively guide you through practical implementation of Tcl/Tk 8.5 commands and tools. This book will take you through all the steps needed to become a productive programmer in Tcl/Tk 8. Right from guiding you through the basics to creating a stand-alone application, it provides complete explanation of all the steps along with handy tips and tricks. The book begins with an introduction to the Tcl shell, syntax, variables, and programming best practices in the language. It then explores procedures and the flow of events with control constructs followed by advanced error trapping and recovery. From Chapter 4, a detailed study of string expressions and handling enables you to handle various string functions and use lists to expand the string functionality. The book then discusses in-depth the Tcl Dictionary and how to utilize it to store and retrieve data. File operations and Tk GUI handling are covered extensively along with a developing a real-world address book application to practice the concepts learned.
Table of Contents (20 chapters)
Tcl/Tk 8.5 Programming Cookbook
About the Author
About the Reviewers

Configuring a file

As mentioned previously, you may use the fconfigure command to set or get the configuration options for an open channel. The syntax is as follows:

fconfigure channel name value name value…

If invoked with no option names or values, the fconfigure command will return the configuration options for the channel specified. Optionally, a configuration name may be passed to get the configurations for the option specified. If name and value pairs are passed the file will be configured based on the name/value pairs supplied.

The syntax of acceptable options and their descriptions are as follows:



-blocking boolean

This determines if the I/O operations can result in indefinite blocking. Acceptable values must be provided in the standard Tcl Boolean format.

-buffering value

If set to full all output is buffered until a flush command is invoked. If set to line, then the system will automatically flush when a newline character is output. If set to none...