Low-Level Screen I/O Services APIs

The low-level services are divided into the following functional groups:

• Screen Manipulation and Query APIs, which are used to query and manipulate the state of the screen.
  
  
• Buffer Manipulation and Query APIs, which are used to create, query, and manipulate input and command buffers used to interact with the screen.
  
  
• Screen Input APIs, which are used to read field data and other information from the screen.
  
  
• Screen Output APIs, which are used to define fields and write data and other information to the screen.

The low-level screen I/O services APIs provide a direct interface to the 5250 data stream commands and user-defined data streams for performing basic screen I/O operations. For detailed information about the results and interactions of these operations, refer to the following 5250 data stream documentation:

• 5250 Functions Reference, SA21-9247-06. This book is not accessible online, but can be ordered from the IBM Publications Center.
  
  
• 5494 Remote Control Unit Functions Reference R3.1, SC30-3533-04. This book can be viewed online through the IBM Publications Center.

For additional information, select one of the following:

• Low-Level Services Examples
• DSM Error Handling
• Device Support
• Operating Environments
• Direct and Indirect Operations
• DBCS Considerations
• Performance Considerations
• Limitations and Restrictions
• 5250 Data Stream Details, including
  • AID-Generating Keys
  • Control Characters
  • Screen Attribute Characters
  • Display Address
  • Insert Cursor Address
  • Modified Data Tag (MDT) Bit
  • Resequencing
  • States and Modes
  • Dumping the 5250 Data Stream Commands