cffi-devel April 2013

cffi-devel@common-lisp.net

16 participants
11 discussions

Problems with nested structs and the newer cffi
by Willem Rein Oudshoorn 18 Aug '13

18 Aug '13

I am encountering some problems with trying to upgrade my old cffi code to the new version from quicklisp. If I use the old code, I get lots of warnings about my structs, that I should use either (:struct ...) or (:pointer (:struct ...)) However whateer I try, I do not seem to get it to work, and I am starting to think there is some issue between me and the new cffi. The main issue is a nested struct definition like this: ``` (defcstruct timeval (time %time) (offset :int)) (defcstruct (git-signature) (name :string) (email :string) (time (:struct timeval))) ``` With type definitions ``` (define-foreign-type time-type () nil (:actual-type :int64) (:simple-parser %time)) (define-foreign-type git-signature-type () nil (:actual-type :pointer) (:simple-parser %git-signature)) ``` I encounter problems when I am trying to update the `translate-to-foreign` for the `git-signature-type`. The implementation boils down to: ``` (defmethod translate-to-foreign ((value list) (type git-signature-type)) (let ((signature (foreign-alloc '(:struct git-signature)))) (with-foreign-slots ((name email time) signature (:struct git-signature)) (setf name (getf value :name (getenv "USER"))) (setf email (getf value :email (default-email))) (with-foreign-slots ((time offset) time (:struct timeval)) (let ((time-to-set (getf value :time (local-time:now)))) (setf time time-to-set) (setf offset (/ (local-time:timestamp-subtimezone time-to-set local-time:*default-timezone*) 60))))) signature) ``` The problem is in the inner `with-foreign-slots ((time offset)...`. The error I get is: ; Evaluation aborted on #<TYPE-ERROR expected-type: SYSTEM-AREA-POINTER datum: (CL-GIT::OFFSET 0 TIME @1970-01-01T01:00:03.000000+01:00)>. The reason is, as far as I can tell, that in the code: (with-foreign-slots ((time offset) time (:struct timeval)) ... the value of `time` is already a plist (due to the outer with-foreign-slots), and the inner with-foreign-slots expects a pointer. So what is the best way of fixing this? I can fix this by replacing the inner `with-foreign-slots` by ``` (with-foreign-slots ((time offset) (foreign-slot-pointer signature '(:struct git-signature) 'time) (:struct timeval)) ``` which seems a bit long. An additional question is, when to use (:struct ...) and when to use (:pointer (:struct ..))) I did expect that I needed to use (:pointer (:struct ..)) in the toplevel `with-foreign-slots`, because the argument is actually a pointer to the struct. But that did not work. As you can tell, I am a bit confused. Hope that someone can give some hints to clear my head. Kind regards, Wim Oudshoorn.

4 10

Groveler and HUGE_VAL
by Zach 26 Apr '13

26 Apr '13

I am trying to grovel the value of HUGE_VAL from math.h. This: (constant (huge-val "HUGE_VAL") :type double-float) doesn't work, presumably because HUGE_VAL isn't a proper float on my system (but rather some special positive infinity double float). I get this error: The value NLOPT::INF is not of type REAL. I need to use HUGE_VAL in the arguments in my NLOpt bindings (hence the package name in NLOPT::INF, though I don't think I even typed INF into the system). I believe that I can't use, say, most-positive-double-float, as there is special behavior when the value HUGE_VAL is used, i.e. it isn't just a large number. Interestingly, I can grovel HUGE_VAL as an integer with value 18446744073709551615 which, presumably, if I used the ieee-floats system: (ieee-floats:decode-float64 18446744073709551615) == HUGE_VAL However, I'm not sure of that and that form naturally produces an overflow error. This is a value that cannot actually be represented as a float, after all. Anyway, I'm not sure that this helps me as I have to pass it to a function that expects a double (actually I pass it as an element in an array of doubles that gets passed to the function): nlopt_result nlopt_set_lower_bounds(nlopt_opt opt, const double* lb); So, I think I need to hold the sizeof(double) bytes in memory (whatever the value of HUGE_VAL is) so that I can write it out to an array later. This is doable, but I am having trouble figuring out the syntax to have the groveler automate the task of getting those sizeof(double) bytes in the first place. Is there a way to deal with this? Even better, is there a way that CFFI makes this much simpler so I can just pass define whatever holds HUGE_VAL as an opaque object that can be used as a double? Even better yet, the value of HUGE_VAL provided by CFFI already and I am just not seeing it? Thanks for reading, any help is appreciated, Zach

3 5

Mailing list Issues
by Barry Fishman 26 Apr '13

26 Apr '13

The references to the cffi-devel mailing list on the web page are broken. I had disabled receiving mail from the list. However, I have suddenly started receiving mail from the list. How do I stop it? -- Barry Fishman

2 1

Error on web page
by Liam Healy 14 Apr '13

14 Apr '13

Under "Getting Started", the home page now says. The latest version is , released on (release notes). Liam

2 1

2013年,企业薪酬还需保密吗
by vincent.Cheng 11 Apr '13

11 Apr '13

1 0

Un mensaje solidario de Ricardo y Alejandra Darin .... .........................ref 0
by axawqpknialwkbaxo_noreply＠yahoo.com 11 Apr '13

11 Apr '13

1 0

小秘书也有春天
by Joan.Niu 11 Apr '13

11 Apr '13

1 0

Fight for superior intimate life
by Charlie Alvarado 11 Apr '13

11 Apr '13

Spend continuous nights of joy http://sedaofset.com/interest.html

1 0

[cffi-devel] cff-tests doesn't load (can't build libffi.so ?)
by Anton Vodonosov 05 Apr '13

05 Apr '13

Hello. (ql:quickload :cffi-tests) doesn't work in the latest quicklisp - 2013-03-12, cffi 0.11.0. It worked in the previous quicklisp. Best regards, - Anton

1 0

[cffi-devel] version 0.11.1 released
by Luís Oliveira 04 Apr '13

04 Apr '13

bugfix: the ABCL backend now loads the required contribs properly. bugfix: some callback bugs were fixed in the ACBL backend. (Thanks to Mark Evenson.) bugfix: the groveller was failing to regenerate its lisp files whenever a grovel- or wrapper-file was modified. -- Luís Oliveira http://r42.eu/~luis/

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cffi-devel April 2013