[splint-discuss] memory leak detection

[Roland Illig]

On Sat, Nov 01, 2003 at 09:58:46PM -0500, David Evans wrote:
> 
> Splint's analysis isn't sophisticated enough to figure this out.  If you
> do,
> 
>         free(this_string);
>         this_string = NULL;
> 
> it will prevent the warning.

I just checked the manual, and in clause 5.2.1#5 it states that

    "After the release obligation is transferred, the original reference
    is a dead pointer and the storage it points to may not be used."

5.2.1#3 says:

    * assign it to an external reference declared with an only annotation

According to these statements, the following program should be ok,
shouldn't it?

------------------------------------------------------------------

typedef /*@only@*/ /*@null@*/ char *cstring;

/*@external@*/ extern cstring make_string(const char *) /*@*/;

extern int main(void)
{
    cstring oldstr = NULL;
    cstring newstr = make_string("newstr");

    if (oldstr == NULL) {
        oldstr = newstr;
        /* oldstr should be live */
        /* newstr should be dead */
    } else {
        free(oldstr);
        oldstr = make_string("oldstr");
        /* oldstr should be live */
        free(newstr);
        /* newstr should be dead */
    }
    free(oldstr);
    return 0;
}

------------------------------------------------------------------

Roland