Since S procedures (analysis and execution via SDF-P) as well as non-S procedures (analysis and execution via SYSFILE) can be called with the CALL-PROCEDURE command, you cannot tell from the call alone which type of procedure is being called. For historical reasons, it is initially assumed that a CALL-PROCEDURE calls a non-S procedure, i.e. the procedure is analyzed first by the SYSFILE system component. Only after this analysis will an S procedure be analyzed by SDF-P.
In contrast to this, the INCLUDE-PROCEDURE command can only be used to call S procedures, i.e. the analysis is always performed by SDF-P.
If the caller does not care about the different variable models that the two command calls are based on, then an S procedure should be called with the INCLUDE-PROCEDURE command. This will avoid the unnecessary analysis by the SYSFILE component.
The call using INCLUDE-PROCEDURE commands can also be defined with SDF-A >= V4.1A for commands implemented in procedures (see the “SDF-A” manual [16]).