demo_module_6 Code Example for Multiple Instance Modules

The demo_module_6 code is located by default in /usr/demo/sma_snmp/demo_module_6. The README_demo_module_6 file within that directory contains instructions that describe how to perform the following tasks:

• Compile source files to generate a shared library object that implements a module

• Set up the agent with an SNMPv3 user

• Set up the agent to dynamically load the module

• Test the module with snmp commands to show that the module is functioning as expected

The demo_module_6 example shows how to write a module that registers an object in two different contexts. The example also shows how to check for the contextName in a request and return a different value depending on the value of the contextName.

demo_module_6 registers one object, filesize, in two different contexts, fileX, and fileY. The OIDs are registered by using a read-only instance handler helper. The OIDs do not need to be read-only. You could also register the OIDs using any of the SMA instance handler helper APIs.

The function get_filesize() is registered to handle GET requests for instances of the filesize object. The get_filesize() function checks the contextName in the reginfo structure that is passed to the function by the SMA. If the value of contextName is fileX, the function returns fileX_data, which has been set to the integer 111. If the value of contextName is fileY, the function returns fileY_data, which has been set to the integer 999.