Use return type c-string* and chicken will free() the memory for you.
Also, your function does not perform a callback to Scheme, so you can
use foreign-lambda instead of foreign-callback-lambda [which is itself
deprecated in favor of foreign-safe-lambda].
On 6/24/05, Andrey Fomichev <[EMAIL PROTECTED]> wrote:
> Hello!
>
> I have a question about memory management in Chicken for c-string values,
> created in an external function.
> Consider a small example below. I have main module in Scheme that calls
> C function 'c-fun'. 'c-fun' does some work and constructs answer (by
> allocating
> and filling memory). Then the resulting string passed back to Scheme-part of
> the program. Is there any memory loss? Another words, does Chicken free this
> memory or I should do it myself. If so, what is the best way?
>
> Thanks in advance,
> Andrey
>
> ===========================================================================
> ; main.scm
> (declare (foreign-declare "char* c_fun(const char*);"))
> (define c-fun (foreign-callback-lambda c-string "c_fun" c-string))
>
> (display (c-fun "Hello, world"))
> (newline)
> ===========================================================================
>
>
> ===========================================================================
> /* f-fun.c */
> #include <stdlib.h>
> #include <string.h>
>
> char* c_fun(char *str)
> {
> int size;
> char *res;
>
> res = (char*)malloc(strlen(str) + 1 + 3);
>
> strcpy(res, str);
> strcpy(res + strlen(str), "!!!");
> res[strlen(str) + 3] = '\0';
>
> return res;
> }
> ===========================================================================
>
>
>
>
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