Apropos

fboundpFunction

    Syntax

    fboundp name generalized-boolean

    Pronunciation

    [ ef bau̇ndpē ]

    Arguments and Values

    name — a function name.

    generalized-boolean — a generalized boolean.

    Description

    Returns true if name is fbound; otherwise, returns false.

    Examples
     (fboundp 'car)  true 
     (fboundp 'nth-value)  false 
     (fboundp 'with-open-file)  true 
     (fboundp 'unwind-protect)  true 
     (defun my-function (x) x)  MY-FUNCTION 
     (fboundp 'my-function)  true 
     (let ((saved-definition (symbol-function 'my-function))) 
       (unwind-protect (progn (fmakunbound 'my-function) 
                              (fboundp 'my-function)) 
         (setf (symbol-function 'my-function) saved-definition))) 
     false 
     (fboundp 'my-function)  true 
     (defmacro my-macro (x) `',x)  MY-MACRO 
     (fboundp 'my-macro)  true 
     (fmakunbound 'my-function)  MY-FUNCTION 
     (fboundp 'my-function)  false 
     (flet ((my-function (x) x)) 
       (fboundp 'my-function))  false
    Exceptional Situations

    Should signal an error of type type-error if name is not a function name.

    See Also

    symbol-function, fmakunbound, fdefinition

    Notes

    It is permissible to call symbol-function on any symbol that is fbound.

    fboundp is sometimes used to “guard” an access to the function cell, as in:

    (if (fboundp x) (symbol-function x))

    Defining a setf expander F does not cause the setf function (setf F) to become defined.