25.1.6.4 C null pointers

It may be convenient to build C null pointers. Several means can be used. In particular, foreign structures and pointers are provided with Null creators. For other foreign types, the easiest one is likely to be a pragma form. For instance, in order to create a null pointer to a double* type, one may use:

(pragma::double* "((double *)0L)")

bigloo procedure: string-ptr-null? string

bigloo procedure: void*-null? void*

These two predicates checks if there argument is the C NULL value.

bigloo procedure: make-string-ptr-null

bigloo procedure: make-void*-null

These two constructors creates null foreign values.