I now boiled it down to a small example.
File call_binop.h:
#ifndef _CALL_BINOP_H_
#define _CALL_BINOP_H_
typedef int (*binop_callback)(int, int);
int call_binop(int a, int b, binop_callback callback);
#endif
File call_binop.c:
#include "call_binop.h"
int call_binop(int a, int b, binop_callback callback)
{
return (*callback)(a, b);
}
I compile call_binop.c to a shared library libcall_binop.so and copy
that to a standard lib directory (there seems to be no way to provide an
-L option and setting LD_LIBRARY_PATH doesn't seem to work either!?)
Then I execute:
c-library binop-call
s" call_binop" add-lib
\c #include "call_binop.h"
c-function call_binop call_binop n n func -- n
c-callback binop n n -- n
end-c-library
: add + ;
' add binop CONSTANT cb_add
2 3 cb_add call_binop
giving:
*the terminal*:1: error: Invalid memory address
2 3 cb_add *call_binop*
If I add .s to the definition of add I see <-35568003> in the output.
So the callback has been executed, but something went wrong and I don't
know how to avoid it.
--
René Hartmann
Am 03.09.2017 um 12:00 schrieb Rene Hartmann:
I'm trying to use the C callbacks available with GForth 0.7.9 but
somehow it doesn't seem to work.
I have a callback that takes two arguments and one return value.
I define it like this:
c-callback cs-renderer n a -- a
' render>buf cs-renderer CONSTANT c_render_to_buf
When passing c_render_to_buf to the function which requires the callback
the callback gets invoked but when it returns things go wrong.
If I place a .s in the callback it prints <-34288843> so it seems the
stack isn't set up properly. But I don't know what to do different to
make it work.
I've yet to create a complete example I can post.
--
René Hartmann
