How is the LOCAL dialplan function susposed to work?

Asterisk Asterisk General
1

Setting a regular variable with the same name as a LOCAL variable will overwrite its value. Consider the following example:

[subLocalTest]
exten => start,1,NoOp()
        same => n,Set(LOCAL(number)=200)
        same => n,NoOp(LOCAL(number)=${LOCAL(number)})
        ; The following two statements (even in another Gosub) will overwrite LOCAL(number) in this sub:
        same => n,Set(number=15)
        ;same => n,Set(ARRAY(name,number)=Eric,15)
        same => n,NoOp(LOCAL(number)=${LOCAL(number)} <expected 200>)
        same => n,Return()

gives you:

-- Executing [300@TheOffice:1] NoOp("SIP/qq-0000002c", "") in new stack
-- Executing [300@TheOffice:2] Answer("SIP/qq-0000002c", "") in new stack
-- Executing [300@TheOffice:3] Goto("SIP/qq-0000002c", "local") in new stack
-- Goto (TheOffice,300,4)
-- Executing [300@TheOffice:4] NoOp("SIP/qq-0000002c", "") in new stack
-- Executing [300@TheOffice:5] Gosub("SIP/qq-0000002c", "subLocalTest,start,1()") in new stack
-- Executing [start@subLocalTest:1] NoOp("SIP/qq-0000002c", "") in new stack
-- Executing [start@subLocalTest:2] Set("SIP/qq-0000002c", "LOCAL(number)=200") in new stack
-- Executing [start@subLocalTest:3] NoOp("SIP/qq-0000002c", "LOCAL(number)=200") in new stack
-- Executing [start@subLocalTest:4] Set("SIP/qq-0000002c", "number=15") in new stack
-- Executing [start@subLocalTest:5] NoOp("SIP/qq-0000002c", "LOCAL(number)=15 <expected 200>") in new stack
-- Executing [start@subLocalTest:6] Return("SIP/qq-0000002c", "") in new stack
-- Executing [300@TheOffice:6] Hangup("SIP/qq-0000002c", "") in new stack

I don’t see the purpose of LOCAL if it’s value can be modified from another Gosub context. Am I missing something obvious here? :slight_smile: (Asterisk 13.14.0-rc2)

2

The wiki[1] has a description of what it is for. It’s a locally scoped variable that after the Gosub returns it is returned to its previous state. Underneath it is doing a normal Set() but maintains state that it cleans up when Gosub returns so it return to the original state.

[1] https://wiki.asterisk.org/wiki/display/AST/Function_LOCAL

3

Thanks for clarifying. Looks like you need to use LOCAL in every sub to keep everything scoped. I was partway through doing that.