I found no documentation on basic memory handling conventions in Axis2/C. Until this content appear under a developer guide for Axis2/C, here are some facts that could be useful in preparing such document. Here I don’t talk about advance facilities provided regarding memory management in Axis2/C. However I’ll provide links below for such documents. I just talk about few points that could be useful for service and client developers in handling memory which are not included in the above mentioned documents.
Memory handling in services
Axis2/C services should be written implementing the API defined in axis2_svc_skeleton.h. Basically if your service name is echo you will have two implementation files echo_skeleton.c and echo.c. echo_skeleton.c will contain the functions implementing the API including life-cycle management functions of the service. They are echo_create(), echo_init(), echo_free, echo_invoke and echo_on_fault(). Within the create function you will instantiate axis2_svc_skeleton_t stuct and assign your services operation structure to the svc_skeleton_t structures operation structure so that your functions will be called from withing the Axis2/C engine.
Within free function you will free the sekelton structure you allocated in create function. When the service unloaded this function is called by the engine to free the service resources. If you allocate any additional stuff withing the service create function it is your responsibility to free them then and there.
In invoke function you can check the operation requested and call the appropriate service function from echo.c where all the service logic functions are implemented. The response nodes if any are created withing these service functions will be freed by the Axis2/C engine. Also any property you set there into Axis2/C configuration context structures will be garbaged by the Axis2/C engine according to their life scope. Any additional stuff you created there must be handled by your self.
In the on_fault function you can create a fault node which could be inserted as detail element in creating soap faults by the engine when something goes wrong when invoking your service. It is the responsibility of the Axis2/C engine to free such nodes.
Memory handling in clients
Most of the memory allocated in the client side (including SOAP request and reply messages), should be cleaned in the client side itself. Memory allocated for properties are taken care of by the SOAP engine. SOAP engine reclaims the memory allocated for properties based on the scope (Request, Session or Application) you set for each property.
You can read more advance information regarding memory management in Axis2/C in the following articles. However some of these articles are old so if you find it is difficult to understand them with the current Axis2/c code base don’t hesitate to ask in the Axis2/C developer list.
