[Vala] Implicit array size for function allocating an array

[Nicolas CARRIER <nicolas carrier parrot com>]

Hello,

I'm trying to bind a C function which has the following prototype:

int sos_addresses_to_string(const struct sos_address *addresses,
                char ***string_addresses, int nb);

It's job is to convert an array of addresses, into an array of their string 
representation. So both the addresses array (in input) and the string_addresses 
array will have the same size which is nb. So in output, string_addresses will 
point to an allocated array of allocated char buffers.

I tried to bind it this way:

namespace Sos {
        public struct Address {
                ...
		public static int array_to_string([CCode (array_length_pos = 3)] Address 
addresses[], [CCode (array_length = false] out string[] string_addresses);
        }
}

and to use it with the following minimal code example:

public static int main(string[] args)
{
        string[] strings;
        Sos.Address[] addrs;
        // the following call just populates the initial addrs array
        Sos.Server.get_server_addresses("mambo", out addrs);
        Sos.Address.array_to_string(addrs, out strings);
        stdout.printf(@"str_addr: $(strings[0])\n");
        return Posix.EXIT_SUCCESS;
}

This approach works, but valgrind complains that the pointed string, in the 
returned array, isn't freed. In fact, in the generated code, _vala_array_free is 
called with an array length of -1, so only the array is freed, not the pointed 
addresses.

I tried to add array_length_cexpr = "addresses.length" but it didn't do 
anything, unless I remove 'array_length = false', but in this case, an extra 
parameter is added and the code doesn't compile any-more.


What would be the best solution to this issue in your opinion ?

Thank you in advance.