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null-pointer-p

Function
Summary

Tests a pointer to see if it is a null pointer.

Package

fli

Signature

null-pointer-p pointer => result

Arguments

pointer

A FLI pointer.

Values

result

A boolean.

Description

The function null-pointer-p is used to determine if a pointer is a null pointer. A null pointer is a pointer pointing to address 0.

If pointer is a null pointer (that is, a pointer pointing to address 0) then result is true, otherwise null-pointer-p returns false.

Example

In the following example a pointer to an :int is defined, and tested with null-pointer-p . The pointer is then freed, becoming a null pointer, and is once again tested using null-pointer-p .

(setq point (fli:allocate-foreign-object :type :int)) (fli:null-pointer-p point) (fli:free-foreign-object point) (fli:null-pointer-p point)
See also

*null-pointer*
pointer-address
pointer-eq

LispWorks Foreign Language Interface User Guide and Reference Manual - 7 Dec 2011

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