Difference between revisions of "ISSET()"
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==Purpose== | ==Purpose== | ||
Function to check whether a variable exists | Function to check whether a variable exists | ||
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==Syntax== | ==Syntax== | ||
ISSET(<variable name>) | ISSET(<variable name>) | ||
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==See Also== | ==See Also== | ||
| − | [[DECLARE]], [[DIMENSION]], [[LOCAL]], [[PARAMETERS]], [[PRIVATE]], [[PUBLIC]], [[RELEASE]], [[STORE]], [[TYPE()]], [[UNSET()]], [[VARTYPE()]] | + | [[DECLARE]], [[DIMENSION]], [[LOCAL]], [[PARAMETERS]], [[PRIVATE]], [[PUBLIC]], [[RELEASE]], [[SET LOCAL]], [[STORE]], [[TYPE()]], [[UNSET()]], [[VARTYPE()]] |
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==Description== | ==Description== | ||
The ISSET() function can be used to check whether a variable exists. ISSET() will return .T. (true) if the variable named <variable name> exists and .F. (false) if it does not exist. Variables can be formally declared ([[PUBLIC]], [[PRIVATE]] etc.) or automatically created when they are assigned a value. | The ISSET() function can be used to check whether a variable exists. ISSET() will return .T. (true) if the variable named <variable name> exists and .F. (false) if it does not exist. Variables can be formally declared ([[PUBLIC]], [[PRIVATE]] etc.) or automatically created when they are assigned a value. | ||
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==Example== | ==Example== | ||
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</code> | </code> | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:Functions]] | [[Category:Functions]] | ||
| − | [[Category: | + | [[Category:Declaring Variables and Arrays]] |
| − | [[Category: | + | [[Category:Lianja VFP Extensions]] |
| + | [[Category:VFP Function Extensions]] | ||
Latest revision as of 08:26, 4 December 2017
Contents
Purpose
Function to check whether a variable exists
Syntax
ISSET(<variable name>)
See Also
DECLARE, DIMENSION, LOCAL, PARAMETERS, PRIVATE, PUBLIC, RELEASE, SET LOCAL, STORE, TYPE(), UNSET(), VARTYPE()
Description
The ISSET() function can be used to check whether a variable exists. ISSET() will return .T. (true) if the variable named <variable name> exists and .F. (false) if it does not exist. Variables can be formally declared (PUBLIC, PRIVATE etc.) or automatically created when they are assigned a value.
Example
if isset(m_var) // m_var exists endif
