Re: How to GET a COUNTER32 variable ????

On Mon, 2005-05-16 at 18:59, Gemma S=E1nchez wrote:

> Now, I need to GET the value of this variable from my program, so I hav=
e=20
> write the next piece of code:
>=20
> peticion =3D snmp_pdu_create(SNMP_MSG_GET);
> snmp_add_null_var(peticion, aeIndLibre_oid, OID_LENGTH(aeIndLibre_oid)=
);

And what is the value of 'aeIndLibre_oid' ?
In particular, is it { ....., 1 } (the OID of the aeIndLibre object)
or { ....., 1, 0 } (the OID of the aeIndLibre *instance*) ?

> auxint =3D snmp_synch_response(sesionAgente, peticion, &respuesta);
> auxint =3D *(respuesta->variables->val.integer);

Do you have some sort of religious object to checking return codes?
First you ought to check the result of 'snmp_synch_response'
to make sure that sending the request worked (auxint =3D=3D STAT_SUCCESS).
Then you ought to check the 'errstat' field of the response PDU,
to make sure that the agent sent back the expected answer.

*Then* (and only then) can you look at the 'variables' list.


> Obviously, I must not use the field "integer" in the union "netsnmp_var=
data"=20
> to get the value of my variable aeIndLibre, because it is not an intege=
r,=20

Wrong.
Counter32 is based on the ASN.1 INTEGER type, so *does* use the
'val.integer' field. But you'll need to cast this to an unsigned
32-bit integer value.

i.e.
u_long c32_value =3D *(ulong*)respuesta->variables->val.integer;

But you *must* check that the request succeeded before trying to
extract this value.

Dave



-------------------------------------------------------
This SF.Net email is sponsored by Oracle Space Sweepstakes
Want to be the first software developer in space?
Enter now for the Oracle Space Sweepstakes!
http://ads.osdn.com/?ad_id=7412&alloc_id=16344&op=click
_______________________________________________
Net-snmp-users mailing list
Net-snmp-users@lists.sourceforge.net
Please see the following page to unsubscribe or change other options:
https://lists.sourceforge.net/lists/...net-snmp-users