I've pushed another update to libffidemo, adding the class DemoFFITypeMappedThing and tests. With Pharo v50647 image's UFFI enhancements, all DemoFFI tests pass.

DemoFFITypeMappedThing allows using the C typedef demo_thing in #ffiCall: function signatures:

DemoFFILibrary>>apiAllocByMappedPointerPointer: handle
    "int alloc_by_pointer_pointer(demo_thing**)"
    ^ self ffiCall: #(int alloc_by_pointer_pointer (demo_thing **handle))

The C and Smalltalk signatures match. The ability to specify #ffiCall: function signatures very much like the actual C function signatures should make it easier to create bindings for UFFI.

The magic of DemoFFITypeMappedThing lies in FFIOpaqueObject, and,

DemoFFILibrary class>>initializeTypeMap
    TypeMap := Dictionary newFromPairs: #(
        demo_thing    FFIOpaqueObject
    )

With the above, UFFI maps (a pointer to) demo_thing in #ffiCall: signature to FFIOpaqueObject.

Compare and contrast with the earlier versions of DemoFFI:

DemoFFILibrary>>apiAllocByPointerPointer: handle
    "int alloc_by_pointer_pointer(demo_thing**)"
    ^ self ffiCall: #(int alloc_by_pointer_pointer (DemoFFIExternalObject *handle))

Tags: FFI