Re: [Vala] Implicit array size for function allocating an array

[Luca Bruno <lethalman88 gmail com>]

On 16/12/2014 10:52, Nicolas CARRIER wrote:
> 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 ?
After the array_to_string call, do strings.length = addrs.length;