Skip to Content
Asterisk: The Future of Telephony
book

Asterisk: The Future of Telephony

by Jim Van Meggelen, Jared Smith, Leif Madsen
September 2005
Intermediate to advanced
408 pages
16h 20m
English
O'Reilly Media, Inc.
Content preview from Asterisk: The Future of Telephony

Name

Eval() — Evaluates any Asterisk variables located within a string

Synopsis

    Eval(newvar=string)

Processes the given string and evaluates any variables contained in the string. The resulting value is assigned to the variable newvar.

This application is used in situations where a string is used in the dialplan, but any variables contained within it need to be evaluated first. This is often the case when the string is retrieved from a database or other external source.

    ; go through some convoluted steps to create a string that contains
    ; the unparsed variable ${UNIQUEID}
    exten => 123,1,Set(ONE=\$)
    exten => 123,2,Set(TWO=$[{UNIQUEID}])
    ; print the values to the console, to make sure it hasn't been parsed
    exten => 123,3,NoOp(${ONE}${TWO})
    ; now evaluate the variables in the string
    exten => 123,4,Eval(TEST=${ONE}${TWO})
    ; print the result to the console
    exten => 123,5,NoOp(${TEST})

See Also

Exec(), ExecIf()

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

Asterisk: The Future of Telephony, 2nd Edition

Asterisk: The Future of Telephony, 2nd Edition

Jim Van Meggelen, Jared Smith, Leif Madsen
How to Develop a Great Digital Strategy

How to Develop a Great Digital Strategy

Jeanne W. Ross, Cynthia M. Beath, Ina M. Sebastian
The Hidden Cost of AI-Assisted Creativity

The Hidden Cost of AI-Assisted Creativity

Léonard Boussioux, Anil Doshi, Oliver Hauser, Kartik Hosanagar

Publisher Resources

ISBN: 0596009623Catalog PageErrata