Synopsis:

 NULL Test: Returns 1 if NULL or 0 otherwise

Description:

 ISNULL(<data>)
 

Notes

• *CLI> show function ISNULL

Return value

Returns 1 if NULL or 0 otherwise.

Example

exten => s,1,Set(foo=${ISNULL(${var1})})

See also

• Asterisk variables
• Asterisk functions

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• Asterisk - documentation of application commands