Verifies if a value is bound to a symbol
Supported Platforms: Windows, Mac OS, and Web
Signature
(boundp sym)
- sym
-
Type: Symbol
A symbol.
Return Values
Type: T or nil
T if sym has a value bound to it. If no value is bound to sym, or if it has been bound to nil, boundp returns nil. If sym is an undefined symbol, it is automatically created and is bound to nil.
Examples
(setq a 2 b nil) nil (boundp 'a) T (boundp 'b) nil
The atoms-family function provides an alternative method of determining the existence of a symbol without automatically creating the symbol.