The system services exit interface contains exits to perform the
following functions:
- Allocate memory
- Free memory
- String identifier service — this is used to create a unique
4 byte numerical value (StringID) that corresponds to a string parsed
from the document. This exit allows the caller to control the individual
StringID values that the z/OS XML parser uses and serves as an efficient mechanism
to communicate these values between caller and parser. If no StringID
service is specified, StringIDs are not exploited by the z/OS XML parser and
the parsed data stream will contain only length/value pairs for all
parsed strings.
These exits are all passed the address of a system service work
area. This work area is storage that was obtained by the caller and
can be used to store any information which may make communication
between the caller and the exits easier.