[AGENT++] Memory management in 3.2.13

[Marek Malowidzki]

Hi,

I would like to submit the following problems in the latest SNMP++ release:
- Collection: there is no memory allocation check in the += operator
- Pdu: the copy constructor checks if memory allocation succeeded but there
is no subsequent check if a Vb has successfully been created (copied in a
copy constructor)
- Pdu: could you consider Pdu::set_notify_*() functions to return bool
instead of void to notify whether the set succeeded? There is no immediate
way to check this.
- could you assure that the only thing modified by Snmp::snmp_engine() on
the supplied target is the engine_id for v3 targets (and only when the
current value is an empty string)? If so, for example, a comment could be
added. It is important to me to provide MT-safety in SNMP++.NET - Snmp
class' communication functions, which are based on snmp_engine(), accept a
non-const pointer to SnmpTarget.

Best regards,

Marek