Exercises, examples and other material relating to training module P305. This module is presented on Private Courses
and Specially Run Courses
Reading data from STDIN and from files is plenty for many applications, but sometimes you'll need to read from the screen without echoing, process input even if the return key is not pressed, or check the keyboard to see if there's input available without pausing your program while the user responds.
|Articles and tips on this subject||updated|
|2876||Different perl examples - some corners I rarely explore|
The private Perl course that I ran on Wednesday through Friday of last week was a little out of the ordinary as we were concentrating far more that usual on a wide variety of practices that may be found - either in legacy code or advanced recent code. Great fun for me, and plenty of new examples.
|2382||Giving up on user input - keyboard timeout in Perl|
There's an old piece of code that I've used to demontstrate how (in Perl) you can prompt for a user input ... but then time out the input on an alarm signal if the user doesn't enter data within a certain time. The code's [here] if you want to have a look. But let me warn you ... it's one of those ...
|2213||Keyboard reading in Perl - character by character not line by line|
If I'm typing in my age in response to a prompt and I start with a "6" character, will you assume that I'm between 60 and 69 years old? You might ... but then I may backspace (having accidentally struck the "6" key and start with a slightly lower digit. But in my program, I do NOT want to have to write ...
Examples from our training material
|ask|| Send a signal to program h1|
|askpw|| Using ioctls and POSIX to provide a password entry system|
|fc2|| Reacting to each keystroke rather than awaiting a new line|
|fi2|| Reporting maximum field per line count|
|file_in|| Unpacking characters|
|h1|| Long running program with interaction|
|kb2|| Giving the user a limited time to make an entry|
|kbcheck|| select to check input availability|
|kbtest|| If the user has started typing, wait for a whole line. Otherwise carry on|
|keyin|| print out ASCII decimal equivalents of entries|
|pcr|| Binary file copy|
Some modules are available for download
as a sample of our material or under an Open Training Notes License
for free download from http://www.training-notes.co.uk
Topics covered in this module
Review of reading input.
Single line keyboard input.
Single line input from a file.
Other sources of single line input.
Checking for input.
Using Fcntl via POSIX.
More flexible reading from a file.
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