[cffi-devel] Cannot call function with char** arg

[Nikolai Nespor]

In reply to James Bielman:

I just managed to do a quick test, I'll have some more time tomorrow.

> Does something like the following work for you?  It'd be nice to
> massage this into something worth including in src/strings.lisp...

[snip]

> ;;; Bind ARGC and ARGV to the count and pointer of a C-style string
> ;;; vector, taking strings from SEQUENCE.  The vector is automatically
> ;;; freed upon exit of BODY.
> (defmacro with-foreign-string-vector ((argc argv sequence) &body body)
>   (cffi-utils:once-only (sequence)
>     `(let* ((,argc (length ,sequence))
>             (,argv (foreign-string-vector ,sequence ,argc)))
>        (unwind-protect
>             (progn , at body)
>          (foreign-string-vector-free ,argv ,argc)))))

If I call it like this (which I hope is right, since I'm just learing lisp)

rrd> (with-foreign-string-vector (argc argv '("create" "test.rrd" "--step=300" "DS:a:GAUGE:600:U:U" "DS:b:GAUGE:600:U:U" "RRA:AVERAGE:0.5:1:300"))
       (rrd-create argc argv))

I get this error:

arithmetic error FLOATING-POINT-INVALID-OPERATION signalled
   [Condition of type FLOATING-POINT-INVALID-OPERATION]

Restarts:
  0: [ABORT-REQUEST] Abort handling SLIME request.
  1: [ABORT] Exit debugger, returning to top level.

Backtrace:
  0: (SB-VM:SIGFPE-HANDLER #<unavailable argument> #.(SB-SYS:INT-SAP #X283822C0) #.(SB-SYS:INT-SAP #X28382000))
  1: (SB-SYS:INVOKE-INTERRUPTION #<CLOSURE (LAMBDA NIL) {49C44A75}>)
  2: ("foreign function: call_into_lisp")
  3: ("foreign function: funcall3")
  4: ("foreign function: interrupt_handle_now")
  5: ("foreign function: interrupt_handle_now_handler")
  6: ("bogus stack frame")
  7: ("foreign function: rrd_create_r")
  8: ("foreign function: rrd_create")
  9: (RRD-CREATE 6 #.(SB-SYS:INT-SAP #X082661C0))
 10: (NIL)
 11: (SB-INT:EVAL-IN-LEXENV (WITH-FOREIGN-STRING-VECTOR (ARGC ARGV (QUOTE #)) (RRD-CREATE ARGC ARGV)) #<NULL-LEXENV>)
--more--

which is further than I ever got before. It would usually bail out before
calling into rrd_create_r - the function where the real work is done.

I'm using SBCL 0.9.9 with SLIME CVS from a few weeks ago on x86 FreeBSD. CFFI
is 0.9.0.

I'll dig deeper tomorrow, thanks for the quick answer

Nikolai

-- 
Ich verwalte sie. Ich zähle sie und zähle sie wieder.
Das ist nicht leicht. Aber ich bin ein ernsthafter Mann.
\\
 ---> Antoine de Saint-Exupery, "Der kleine Prinz"
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