[ˌefˈba.undpē]
name—a function name.
generalized-boolean—a generalized boolean.
Returns true if name is fbound; otherwise, returns false.
(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
Should signal an error of type type-error
if name is not a function name.
symbol-function, fmakunbound, fdefinition
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.