cffi-devel January 2006

cffi-devel@common-lisp.net

34 participants
97 discussions

[cffi-devel] Re: varargs (again)
by Hoehle, Joerg-Cyril 13 Jan '06

13 Jan '06

Hi, Brad Anderson wrote: >I saw some topics in the archives about varargs, First, I have to repeat that interfacing to varargs is, hm... challenging. You cannot expect to be able to use varargs functions portably. It may still work in some cases, and possibly all the cases that you need, but there's no general solution yet, neither within most Lisp implementations, nor for many other programming language environments. Luis' and James' talk about how it could/would look like at the cffi level, when it will work. But that does not make the low-level machinery be able to use varargs in general. Yet the few cases that you need may still work. That said, I'd prefer a single defcfun with a possible &rest marker, than another defcfun-varargs entry point. Oh well, that's a matter of endless debate. E.g. for my AFFI (10 years ago), I had separate defining forms, whereas Sam Steingold in clisp unified all (library or module) into ffi:def-call-out distinguished by the presence of (:library #). In the long run (varargs fully supported), it presumably makes no sense to have two defining entry points. A keyword variation is enough to deal with the special case. IMHO it's just now that we want to distinguish both, perhaps because one works, and the other not, or because one is well-defined, and the other still gathering ideas. Luis Oliveira wrote: > (defcfun "xmlParserError" :void > (ctx :pointer) > (msg :string)) > (defun xml-parser-error (control-string &rest args) > (xmlParserError <whatever-a-ctx-is> > (format nil "~?" control-string args))) Here you allow your application to crash when given strings containing "%" characters. A safe approach would be as follows (defcfun "xmlParserError" :void (ctx :pointer) (formatter :string) ; constantly pass "%s" here (msg :string)) (xmlParserError <ctx> "%s" (apply #' format nil control-string args)) ;; Do all the formatting on the Lisp side ;; Tell the C side to *not* format! I just had to fix a bug in CLISP's syscalls module: posix:syslog() exhibited exactly this stack overflow vulnerability! Calling posix:syslog() with unknown strings could crash it. Regards, Jörg Höhle.

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[cffi-devel] varargs (again)
by Brad Anderson 13 Jan '06

13 Jan '06

Hi, I saw some topics in the archives about varargs, but none answered how I might do this: ------------ xmlParserError (void *ctx, const char *msg, ...); ------------ SWIG (CFFI) produced this: ------------ (defcfun ("xmlParserError" xmlParserError) :void (ctx :pointer) (msg :string) (arg2 )) ------------ Is there any way I could use &rest here? or one big pointer? I don't quite know how to proceed... Cheers, Brad

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[cffi-devel] How to create bindings for variadic function
by Richard Ray 13 Jan '06

13 Jan '06

Can y'all offer pointers/examples of how to create bindings for a variadic function? Specifically TIFFGetField in the libtiff library. Thanks Richard

2 1

[cffi-devel] New patches: 12-Jan-2006
by loliveira＠common-lisp.net 12 Jan '06

12 Jan '06

Thu Jan 12 19:52:01 CET 2006 Luis Oliveira <loliveira(a)common-lisp.net> * Documentation changes - Add some comments about define-foreign-library's new features. The t clause and :default. - Remove (setf get-callback) from the documentation. M ./doc/cffi-manual.texinfo -6 +8 M ./src/libraries.lisp -2 +5 An updated tarball of CFFI's source can be downloaded here: http://common-lisp.net/project/cffi/tarballs/cffi-060112.tar.gz

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[cffi-devel] void arg type
by Brad Anderson 12 Jan '06

12 Jan '06

Hi all, I'm having issues with using :void as a type in certain places. I'm trying to wrap the following in CFFI: struct _xmlAttribute { void *_private; /* application data */ xmlElementType type; /* XML_ATTRIBUTE_DECL, must be second ! */ const xmlChar *name; /* Attribute name */ struct _xmlNode *children; /* NULL */ struct _xmlNode *last; /* NULL */ struct _xmlDtd *parent; /* -> DTD */ struct _xmlNode *next; /* next sibling link */ struct _xmlNode *prev; /* previous sibling link */ struct _xmlDoc *doc; /* the containing document */ struct _xmlAttribute *nexth; /* next in hash table */ xmlAttributeType atype; /* The attribute type */ xmlAttributeDefault def; /* the default */ const xmlChar *defaultValue; /* or the default value */ xmlEnumerationPtr tree; /* or the enumeration tree if any */ const xmlChar *prefix; /* the namespace prefix if any */ const xmlChar *elem; /* Element holding the attribute */ }; ----------------------------------------------- SWIG for CFFI produced: (defcstruct _xmlAttribute (_private :void) (type :pointer) (name :unsigned-char) (children :pointer) (last :pointer) (parent :pointer) (next :pointer) (prev :pointer) (doc :pointer) (nexth :pointer) (atype :pointer) (def :pointer) (defaultValue :unsigned-char) (tree :pointer) (prefix :unsigned-char) (elem :unsigned-char)) ----------------------------------------------- And SBCL 0.9.7 produced: cannot use values types here [Condition of type SIMPLE-ERROR] Restarts: 0: [RETRY] Retry performing #<ASDF:COMPILE-OP NIL {92EA579}> on #<ASDF:CL-SOURCE-FILE "libxml2" {92E6E89}>. 1: [ACCEPT] Continue, treating #<ASDF:COMPILE-OP NIL {92EA579}> on #<ASDF:CL-SOURCE-FILE "libxml2" {92E6E89}> as having been successful. 2: [ABORT] Abort SLIME compilation. 3: [ABORT-REQUEST] Abort handling SLIME request. 4: [TERMINATE-THREAD] Terminate this thread (#<THREAD "repl-thread" {91B5D81}>) Backtrace: 0: (SB-ALIEN::ALIEN-VALUES-TYPE-TRANSLATOR (VALUES) #<NULL-LEXENV>) 1: (CFFI-SYS:%FOREIGN-TYPE-ALIGNMENT :VOID) 2: (CFFI::ADJUST-FOR-ALIGNMENT :VOID 0 :NORMAL T) 3: (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION CL-LIBXML2::_XMLATTRIBUTE ((CL-LIBXML2::_PRIVATE :VOID) (TYPE :POINTER) (CL-LIBXML2::NAME :UNSIGNED-CHAR) (CL-LIBXML2::CHILDREN :POINTER) (LAST :POINTER) (CL-LIBXML2::PARENT :POIN$ 4: (SB-INT:EVAL-IN-LEXENV (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION (QUOTE CL-LIBXML2::_XMLATTRIBUTE) (QUOTE (# # # # # # # # # # ...))) #<NULL-LEXENV>) 5: ((FLET SB-C::DEFAULT-PROCESSOR) (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION (QUOTE CL-LIBXML2::_XMLATTRIBUTE) (QUOTE (# # # # # # # # # # ...)))) 6: (SB-C::PROCESS-TOPLEVEL-FORM (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION (QUOTE CL-LIBXML2::_XMLATTRIBUTE) (QUOTE (# # # # # # # # # # ...))) ((EVAL-WHEN (:COMPILE-TOPLEVEL :LOAD-TOPLEVEL :EXECUTE) (CFFI::NOTICE-FOREIGN-STR$ 7: (SB-C::PROCESS-TOPLEVEL-PROGN ((CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION (QUOTE CL-LIBXML2::_XMLATTRIBUTE) (QUOTE #))) ((EVAL-WHEN (:COMPILE-TOPLEVEL :LOAD-TOPLEVEL :EXECUTE) (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION # #)) $ 8: (SB-C::PROCESS-TOPLEVEL-FORM (EVAL-WHEN (:COMPILE-TOPLEVEL :LOAD-TOPLEVEL :EXECUTE) (CFFI::NOTICE-FOREIGN-STRUCT-DEFINITION (QUOTE CL-LIBXML2::_XMLATTRIBUTE) (QUOTE #))) (SB-C::ORIGINAL-SOURCE-START 0 46) NIL) 9: ((FLET SB-C::DEFAULT-PROCESSOR) (CFFI:DEFCSTRUCT CL-LIBXML2::_XMLATTRIBUTE (CL-LIBXML2::_PRIVATE :VOID) (TYPE :POINTER) (CL-LIBXML2::NAME :UNSIGNED-CHAR) (CL-LIBXML2::CHILDREN :POINTER) (LAST :POINTER) (CL-LIBXML2::PARE$ 10: (SB-C::PROCESS-TOPLEVEL-FORM (CFFI:DEFCSTRUCT CL-LIBXML2::_XMLATTRIBUTE (CL-LIBXML2::_PRIVATE :VOID) (TYPE :POINTER) (CL-LIBXML2::NAME :UNSIGNED-CHAR) (CL-LIBXML2::CHILDREN :POINTER) (LAST :POINTER) (CL-LIBXML2::PARENT $ 11: (SB-C::SUB-SUB-COMPILE-FILE #<SB-C::SOURCE-INFO >) 12: ((LAMBDA NIL)) 13: (SB-C::%WITH-COMPILATION-UNIT #<CLOSURE (LAMBDA NIL) {934352D}>) 14: (SB-C::SUB-COMPILE-FILE #<SB-C::SOURCE-INFO >) 15: (COMPILE-FILE #P"/home/brad/dev/lisp/cl-libxml2/src/libxml2.lisp") 16: ((SB-PCL::FAST-METHOD ASDF:PERFORM (ASDF:COMPILE-OP ASDF:CL-SOURCE-FILE)) #<unavailable argument> #<unavailable argument> #<ASDF:COMPILE-OP NIL {92EA579}> #<ASDF:CL-SOURCE-FILE "libxml2" {92E6E89}>) 17: ((LAMBDA (SB-PCL::.PV-CELL. SB-PCL::.NEXT-METHOD-CALL. SB-PCL::.ARG0. SB-PCL::.ARG1.)) #<unavailable argument> #<unavailable argument> #<ASDF:COMPILE-OP NIL {92EA579}> #<ASDF:CL-SOURCE-FILE "libxml2" {92E6E89}>) 18: ((LAMBDA NIL)) 19: (SB-C::%WITH-COMPILATION-UNIT #<CLOSURE (LAMBDA NIL) {932F0CD}>) Thoughts? Thanks, Brad

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[cffi-devel] How to create bindings for variadic function
by Richard Ray 12 Jan '06

12 Jan '06

Can y'all offer pointers/examples of how to create bindings for a variadic function? Specifically TIFFGetField in the libtiff library. Thanks Richard

1 0

[cffi-devel] New patches: 11-Jan-2006
by loliveira＠common-lisp.net 11 Jan '06

11 Jan '06

Wed Jan 11 22:38:59 CET 2006 Luis Oliveira <loliveira(a)common-lisp.net> * Massage doc/colorize-lisp-examples.lisp a bit - Small hack to colorize-lisp-examples to make it treat "smalllisp" blocks like the normal "lisp" code blocks. M ./doc/colorize-lisp-examples.lisp -3 +7 Wed Jan 11 19:38:40 CET 2006 Stephen Compall <scompall(a)nocandysw.com> * Import the tutorial - "An Introduction to Foreign Interfaces and CFFI" added to manual. M ./doc/cffi-manual.texinfo -9 +1228 Wed Jan 11 17:29:18 CET 2006 Luis Oliveira <loliveira(a)common-lisp.net> * fix load-foreign-library bug When loading a library defined with DEFINE-FOREIGN-LIBRARY, it was processing all the clauses that returned true instead of only the first. Thanks to Stephen Compall for the bug report. M ./src/libraries.lisp -2 +3 An updated tarball of CFFI's source can be downloaded here: http://common-lisp.net/project/cffi/tarballs/cffi-060111.tar.gz

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[cffi-devel] bits from a new tutorial
by Stephen Compall 11 Jan '06

11 Jan '06

I am writing a CFFI tutorial, to be integrated into the manual when it is done if the maintainers will have it. You can get the first half or so in Texinfo format if you so desire at http://csserver.evansville.edu/~sc87/cffi/tutorial.texi . You can integrate it into cffi-manual.texi for building (if you want to see TeX, HTML, etc output) with a @include tutorial.texi For best results, put it where that comment about the manual needing a tutorial is. If you want curl.h and easy.h to follow along, they are in the same directory. Stuff left to be written about: * Dealing with memory allocation. The importance of the "Breaking the abstraction" section should become clearer here. * define-foreign-type for bits to be LOGIORed, then using that to type the input to curl_global_init. * Writing type translators. This will be used to restrict the :curl-easy-handle type. * Callbacks. This of course will be a :writefunction. * I think that error CURLcodes should "translate" to conditions. However, that is mostly macrology rather than new CFFI material, so I am not sure it should be included. * Some other stuff I can't remember right now. It depends on what I can reasonably introduce in the context of the example I've chosen. I may also consider disjoining the TYPEs in the :curl-option definition. After all, I'm breaking the abstraction, so I might as well make a better one. Some notes may be confusing at the moment. If you see one, please tell me anyway, in case it is not one I am thinking of. There is a stray TODO, and I don't yet know how I'm going to type curl_off_t portably. I will probably just remove :off-t for this tutorial. Comments are of course welcome here, and especially on Freenode #lisp, where I am S11001001. -- Stephen Compall http://scompall.nocandysw.com/blog

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[cffi-devel] New patches: 10-Jan-2006
by loliveira＠common-lisp.net 10 Jan '06

10 Jan '06

Tue Jan 10 14:57:50 CET 2006 James Bielman <jamesjb(a)jamesjb.com> * fix DISCARD-DOCSTRING to not treat a singleton string as a docstring - Callback bodies consisting of only one string literal were treated as docstrings instead of being returned. - Added a test case in callbacks.lisp for this. Thanks to ignas on #lisp for the bug report. M ./src/utils.lisp -3 +4 M ./tests/callbacks.lisp -1 +9 An updated tarball of CFFI's source can be downloaded here: http://common-lisp.net/project/cffi/tarballs/cffi-060110.tar.gz

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AW: [cffi-devel] New foreign library interface
by Hoehle, Joerg-Cyril 10 Jan '06

10 Jan '06

James Bielman wrote: >This is emphatically *not* a reimplementation of UFFI's library code. Ok. I'll shut up until I have time to investigate what it looks like. >For system libraries, there should not ever be a need to specify a >directory in DEFINE-FOREIGN-LIBRARY. Please emphasize this in the documentation! I've seen enough software documentation that does not explain how to actually use the software: what functions are important, which are helpers, etc. >*FOREIGN-LIBRARY-DIRECTORIES* exists as an escape hatch for users that >want to extend this behavior Same plead. Please state that in the documentation, so hopefully people will not make wrong assumptions (e.g. "I need to set the directory because that's what I'm used to with language XYZ" would be wrong here). > (:linux (:or "libGL.so.1" "libGL.so")) >The "libGL.so" entries are there as a fallback, That makes a lot of sense. Please provide such examples/recommendations in the documentation. (which of course raises the problem of untested code: the developer probably has libGL.so.1 on his machine and may not test the other case. So the other case is an "educated guess" :). >I disagree---these aren't wild guesses; the developer of a library >should know what version of a library he is linking against, and >document this information for each platform he's tested on. [similar idea as here:] >IMHO, if I'm going to link against symbols in a shared library, I had >better be aware of what major version I'm loading. My experience is different, perhaps because I've seen mostly bindings, not applications. Bindings may have the property that they want to be as little restrictive as possible. E.g. Bindings for postgres 7 may still work with postgresql8, and vice-versa. Regards, Jorg Hohle.

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cffi-devel January 2006