On Wed, Apr 07, 2021 at 07:46:20AM +0200, Alexander Burger wrote:
> OK, so now we have a pointer to a structure filled by evalInR().
> ...
> (struct (evalInR "6*4") ...)
In fact this depends on what exactly evalInR() returns.
If it returns a pointer to a dynamically allocated structure, and the caller is
responsible to de-allocate it, you would do
(let P (evalInR "6*4")
(prog1
(struct P ...)
(free P) ) )
If, however, the structure is statically allocated, you can also give the
structure's structure directly as the return value specification:
(native `*RinC "evalInR" '(...) "Cmd")
For example, as a (somewhat conceived) test case
static struct {
char *s;
int i[4];
double d;
char nm[8];
} Data;
void *foo(void) {
Data.s = "Hello";
Data.i[0] = 1;
Data.i[1] = 2;
Data.i[2] = -3;
Data.i[3] = 4;
Data.d = 0.99;
strcpy(Data.nm, "world");
return &Data;
}
Then in the REPL
: (native "./test.so" "foo" '(S I (I . 2) (B . 4) 100 (C . 8)))
-> ("Hello" 1 (2 -3) (4 0 0 0) 99 ("w" "o" "r" "l" "d"))
☺/ A!ex
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