In the rare cases you need to do this sort of check why not just write a simple sizeof test?
[eric@rangely foo]$ cat foo.c
#include <stdio.h>
int test (int arr[10])
{
printf ("%lu\n", sizeof (arr));
return 0;
}
int main (int argc, char *argv[])
{
int arr[5];
test (arr);
return 0;
}
8
(EDIT: fixed formatting)
More to a style/safety point, if I ever see a function that expects an array and doesn't also take the size of that array as another parameter, that's a bug waiting to happen.
Especially in this case since this feature seems to only throw a warning on recent versions of clang, and more or less nothing else.