[Openmcl-devel] Question about foreign-functions
tuscland at mac.com
Fri Nov 21 00:16:12 UTC 2003
I am Camille, and I am new to this list.
I am building a web server application with PortableAllegroServe with
webaction and CL-SQL with OpenMCL on Mac OS X 10.3.
I am getting some problems with FFI : Here is a code sample that
doesn't work. It is very likely that I am wrong, because I just start
writing Lisp programs.
This function is supposed to call the function "stat", access the
st_ino field of the structure and return the result which is
(supposedly) an int.
(defun filesys-inode (path)
(let ((checked-path (probe-file path)))
(rlet ((pstat (:* (:struct stat))))
(with-cstrs ((str (namestring checked-path)))
(#_stat str pstat))
(pref pstat :stat.st_ino)))
(t (error "path ~s does not exist" path)))))
If I call this function I get this error :
> Error in process listener(1): value 0 is not of the expected type
> While executing: "Unknown"
If I put a "print" form around the pref call, the result I correctly
printed on the standard output and then the error arises. A look to
the backtrace confirms that the error occurs outside of the
If I replace rlet with rletz I get the following compilation error
which I don't understand:
> Error in process listener(1): While compiling FILESYS-INODE :
> #1=(PSTAT (:* (:STRUCT STAT))) is not a
symbol or lambda expression in the form (#1#) .
I think that I must pass #_stat a reference to a stack allocated
The problem is that:
1. I don't know how to pass a reference to a stack allocated object to
2. I don't know how to declare a stat structure object because if I
(rlet ((pstat (:struct stat)))
I get a compilation error.
Thanks in advance for any help!
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