Re: [clisp-list] verify FFI-code, plz

[Yaroslav K. <kav...@je...>]

Joe...@t-... wrote:
> >  This is example of c-code (mix from .h and .c files):
>    
> It is generally not possible *without API documentation* to translate
> C's poor type declarations to CLISP's rich FFI. C does not tell you
> anything about :in, :out or :in-out. Only the docs do.
>    
Ok, but all documentation it is source:
http://llvm.org/svn/llvm-project/llvm/trunk/include/llvm-c/Core.h
http://llvm.org/svn/llvm-project/llvm/trunk/include/llvm-c/Analysis.h

> Please always provide a link to the documentation when asking such questions.
>    
ok, excuse me
And many thanks for your answer.

> Looking at your C code,
>>    char *error = NULL; // Used to retrieve messages from functions
>>    error = NULL;
>>    if(LLVMCreateJITCompiler(&engine, provider, 2,&error) != 0) {
>>      
>       LLVMDisposeMessage(error);
> I'd say you're better off using an explicit c-pointer for [out]error using
> with-foreig-object or with-c-var
>   - to keep the original pointer (for DisposeMessage)
>   - to deref the string only when an error occurred (like you do in C).
>     (with-foreign-object (ptr 'c-pointer NULL)
>        (when (create ... ptr)
>           (princ (mem-read ptr 'c-string))
>           (disposemessage ptr)))
>    
ok, but "NULL" is "NIL"? And what is "mem-read"?

and last: 'LLVMCreateJITCompiler' require 'char **OutError'
but 'LLVMDisposeMessage' require 'char *Message'
The code will be by the same?
>     (with-foreign-object (ptr 'c-pointer)
>        (when (LLVMCreateJITCompiler ... ptr)
>           ...
>           (LLVMDisposeMessage ptr)))
and how declare argument OutError in LLVMCreateJITCompiler - as
               (OutError ffi:c-pointer)
or as
               (OutError (ffi:c-ptr ffi:c-pointer))
?
Many thanks for your answer again.

-- 
WBR, Yaroslav Kavenchuk