What happens to PROC steps in SAS supervisor?

[mikepark]

I have read a lot about DATA steps and how the role of the PDV. However, when the data gets to the PROC step. What happens? It seems like there is not as much literature on this but maybe I am wrong. 

[Kurt_Bremser · Accepted solution]

While a data step is always compiled from the code, procedures are pre-compiled modules that are fed with parameters according to your coding. While data step is a "turing-complete" language, procedures have a fixed limited set of capabilities, and therefore there is no need of an in-depth description of the workings.

[Rick_SAS]

Do you have a specific question about a specific procedure?

In general, the procedure reads one observation at a time from a SAS data set. Before the procedure sees any data, the data are filtered by any data set options, such as DROP, KEEP, RENAME, and WHERE clauses. Thus, the procedure sees only the filtered data.