Embedded IO Methods

This table lists the embedded IO methods used with the Historical File Splitting utility:

Method	Description
*POST_OPEN()**	This function is invoked immediately following the OPEN of the file and is passed the original pathname specified, the file channel number and the actual full pathname for the file.
*PRE_CLOSE()**	Called just before the file closed. Should close all associated data files.
*PRE_READ()**	Called before the file is read and will need to perform the actual READ request on the appropriate file.
*PRE_WRITE()**	Called before the file will be written to and will output/update the record onto the proper data file. Before issuing the actual write, any UNIQUE keys will be validated against the associated data files.
*PRE_REMOVE()**	Called just before the record should be removed from the file. If the record exists in the 'active' file, it will be removed; otherwise, a file access error will be generated.
*PRE_PURGE()**	If *only* the 'active' file is defined, the 'active' file will be cleared; otherwise, an error will be generated.
*KEF() / KEL()*	Called to return the first/last key on the file. This routine will return the lowest/highest key on all associated files.
*KEC()**	Called to return the current key. Will return the current key on the last file accessed by a READ/WRITE/REMOVE.
*KEY() / KEP()*	Called to return the next/prior key on the file. This routine will need to determine what would be the next/prior logical key for all the associated files.
*FIN(,"NUMREC")**	This specific FIN function will return the sum of the number of records on all associated files.