SNMP clients may use these packages, but this usage is currently untested: the reason why this port to eCos exists is to acquire the SNMP agent. The fact that that the SNMP API (for clients) exists is a side-effect. See the standard man page SNMP_API(3) for details. There are further caveats below about client-side use of the SNMP library.
All of the SNMP header files are installed beneath .../include/ucd-snmp in the install tree. The SNMP code itself assumes that directory is on its include path, so we recommend that client code does the same. Further, like the TCP/IP stack, compiling SNMP code requires definition of _KERNEL and __ECOS, and additionally IN_UCD_SNMP_SOURCE.
Therefore, add all of these to your compile lines if you wish to include SNMP header files:
-D_KERNEL -D__ECOS -DIN_UCD_SNMP_SOURCE=1 -I$(PREFIX)/include/ucd-snmp