Enscribe Programmer's Guide

No Automatic Update........................................................................................................34
Alternate Keys in a Key-Sequenced File.................................................................................34
Alternate Keys in an Entry-Sequenced File.............................................................................34
Alternate Keys in a Relative File............................................................................................34
Alternate-Key Files..............................................................................................................34
Alternate Keys and Record Locking.......................................................................................35
Relational Access...............................................................................................................37
3 System Procedures....................................................................................39
File-System Procedures.............................................................................................................39
Procedure Call Completion..................................................................................................41
File Number Parameters......................................................................................................42
Tag Parameters..................................................................................................................42
Buffer Parameter................................................................................................................42
Transfer Count Parameter....................................................................................................42
Condition Codes...............................................................................................................42
Error Numbers...................................................................................................................43
File Access Permissions.......................................................................................................43
External Declarations..........................................................................................................44
Sequential I/O (SIO) Procedures..............................................................................................44
4 General File Creation and Access Information..............................................46
File Creation..........................................................................................................................46
File Codes........................................................................................................................46
Disk Extent Sizes................................................................................................................46
File Formats Supported: Format 1 and Format 2.....................................................................46
File Size Limits...................................................................................................................48
Audit-Checkpoint Compression............................................................................................49
Write Verification...............................................................................................................50
File Access.............................................................................................................................51
Opening and Closing Files..................................................................................................51
Opening Partitioned Files....................................................................................................51
Read Reverse With Structured Files.......................................................................................52
File Expiration Dates...........................................................................................................53
File Creation and Last-Opened Timestamps...........................................................................53
Using CONTROL 27 to Detect Disk Writes............................................................................53
Using Cache Buffering or Sequential Block Buffering...............................................................54
Sequential Block Buffering...................................................................................................55
Specifying the Appropriate Disk File ACCESSTYPE Parameter...................................................57
Refreshing the End-of-File (EOF) Pointer.................................................................................58
Purging Data.....................................................................................................................58
Programmatically Allocating File Extents................................................................................59
Programmatically Deallocating File Extents............................................................................59
5 Unstructured Files.....................................................................................60
Enscribe Unstructured Files.......................................................................................................60
Applicable System Procedures..................................................................................................60
Types_Access.........................................................................................................................60
Creating Unstructured Files.......................................................................................................61
Buffer Size........................................................................................................................61
Disk Extent Size.................................................................................................................61
Example: Creating an Unstructured File.................................................................................62
Accessing Unstructured Files.....................................................................................................63
File Pointers.......................................................................................................................63
Sequential Access..............................................................................................................64
Random Access.................................................................................................................66
4 Contents