iSeries System Files - IBM-ILE

An ILE C stream file or record file is the same as an iSeries Data Management system file. System files are also called file objects. Each iSeries Data Management system file or file object is differentiated and categorized by information that is stored within it. Each file has its own set of unique characteristics, which determine how the file can be used and what capabilities it provides. This information is called the file description.

The file description also contains the file’s characteristics, details on how the data associated with the file is organized into records, and how the fields are organized within these records. Whenever a file is processed, the operating system uses the file description. Data is created and accessed on the system through file objects. The iSeries Data Management system files are listed:

  • Database files store data on the iSeries Data Management system.
  • Device files provide access to externally attached devices such as: displays, printers, tapes, and diskettes.
  • Intersystem communications function (ICF) files define the layout of the data sent and received between two application programs on different systems. This file links the configuration objects that are used to communicate with the remote system
  • Save files save data in a format that is used for backup and recovery purposes.
  • Distributed Data Management (DDM) files access data on remote systems.

File Naming Conventions

The _Ropen() and _fopen() functions that refer to iSeries system files require a file-name. This file name must be a null ended string.The syntax of an iSeries data management file name is:

File Naming Conventions

Enter the name of the library that contains the file. If you do not specify a library, the system searches the job’s library list for the file.

Enter the name of the file. This is a required parameter.

Enter the name of the file member. If you do not specify a member name, the first member (*FIRST) is used.

Note: If you specify *ALL for member-name when using fopen() and _Ropen(), multi-member processing occurs.

All characters specified for library-name, file-name, or member-name are folded to uppercase unless you surround the string by the back slash and quotation mark (″) control sequence. This allows you to specify the OS/400 quoted names. For example:

Library is: "tstlib"
File is: TSTFILE
Member is: TSTMBR

If you surround the file name, library name,or member name in double quotation marks and the name is a normal name, the double quotation marks are discarded by the ILE CC++ compiler. A normal name is any file, library, or member name with the following characters:

  • Uppercase characters
  • Numeric values
  • $ (hexadecimal value 0x5B)
  • @ (hexadecimal value 0x7C)
  • # (hexadecimal value 0x7B)
  • _ (hexadecimal value 0x6D)
  • . (hexadecimal value 0x4B)

The following characters cannot appear anywhere in your file names, library names, or member names:

Incorrect Character
Hexadecimal Representation
( 0x4D
* 0x5C
) 0x5D
/ 0x6I
″ 0x7F

Note: ″( ) / ″ can be used in quoted file names.

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