[sr-dev] question about module function arguments

[Andrei Pelinescu-Onciul]

On Oct 09, 2010 at 17:25, Juha Heinanen <jh at tutpro.com> wrote:
> i understood that module functions can now have an arbitrary number of
> string, int and pseudo var arguments, where string arguments can
> possibly also contain pseudo variables.
> 
> some time ago i asked an example on how this is done, but didn't get any
> reply.  so i'll try again.  for example, allow_trusted function is
> now defined like this:
> 
> 	{"allow_trusted",  (cmd_function)allow_trusted_2,  2, fixup_pvar_pvar,
> 	        fixup_free_pvar_pvar, REQUEST_ROUTE | FAILURE_ROUTE},
> 
> how can i add a third argument to the function without needing to define
> yet another fixup_pvar_pvar_something?

You cannot use fixup_pvar_pvar for more then 2 parameters. A lot of the
 fixup functions check the number of parameters and return error for
 more then 2.
However in the case of fixup_pvar_pvar(), you can replace it with
 fixup_pvar_all() (and fixup_free_pvar_all).


In your case replacing 2 with 3 and pvar_pvar with pvar_all should work,
e.g.:
{"allow_trusted3",  (cmd_function)allow_trusted_2,  3, fixup_pvar_all,
        fixup_free_pvar_all, REQUEST_ROUTE | FAILURE_ROUTE},

You can use this way to define functions that accept up to 6 parameters.

If you don't care about pvar arguments in strings (which IMHO should be
slowly obsoleted), then you can write a normal module function that
accepts strings as parameters (uses directly the char* arguments,
without any get_str_fparam(...))  and set the fixups to 0. The core will
take care and convert the arguments to string before calling your
function.


I you want variable number of parameters, the module function
declaration should look like:
    {"foov", (cmd_function)foo_var, VAR_PARAM_NO, 0, 0,  REQUEST_ROUTE}

static int foo_var(struct sip_msg* msg, int argc, action_u_t argv[])
{
    int i;
    for (i = 0; i < argc; i++)
        do_something(argv[i].u.string);
    return 1;
}

If you want to use fixups and variable number of parameters, the fixups
 look the same way as normal fixups (fixup(void** param, int param_no)).

For more examples see modules_s/print/print.c (uses the ser modules
interface without free_fixup, but that's the only difference).


Andrei