Question 1

How do I install and set up CFFI in my Common Lisp project?

Accepted Answer

Install CFFI via Quicklisp or ASDF, then refer to the manual for implementation-specific backend setup. For C2FFI features, you'll need to install the c2ffi binary and Clang separately, which can add complexity.

Question 2

Should I use CFFI or the native FFI of my Lisp implementation?

Accepted Answer

Use CFFI if you need portability across different Common Lisp implementations or prefer declarative bindings. Stick with native FFI for single-implementation projects or when maximum performance and direct control are critical.

Question 3

How can I generate CFFI bindings from C header files automatically?

Accepted Answer

Use the CFFI/C2FFI toolchain: run c2ffi on the headers to produce JSON, then use CFFI to generate Lisp code. However, this process isn't fully documented, so check example projects like hu.dwim.zlib for guidance.

Question 4

Does CFFI support passing C structs by value?

Accepted Answer

Yes, but it requires the CFFI-LIBFFI subsystem and libffi library to be available and properly configured, as noted in the README under the CFFI-LIBFFI section.

Question 5

What are the performance costs of using CFFI compared to direct C calls?

Accepted Answer

CFFI adds an abstraction layer that may introduce minor overhead in function calls and memory management. For most applications, the portability benefits outweigh this, but benchmark critical paths if performance is a concern.

Question 6

Is CFFI compatible with all Common Lisp compilers?

Accepted Answer

CFFI aims for portability and has backends for major implementations like SBCL, CCL, and others. Check the documentation or project page for specific support, as some edge cases might require adjustments.

CFFI

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