[AGENT++] How to get muliti-vb in a pdu

[???163]

Hi,

I have used snmp++ to collect interface performance data from network
device.
A pdu sent to the device with 20 vbs only returns a pdu that holds 18 vbs.
How could I increase the size of returned package?
Could I just adjust the MAX_SNMP_PACKET value in config_snmp_pp.h to a big
one that works?
Or should I call get_next to get remain vbs?
If get_next is the solution, are the vbs in the next package unabridged?

Thanks in advance,

Moore