Using EHLLAPI with VA Smalltalk parts
You can use VA Smalltalk to build a workstation-based, graphical user interface that can access host applications designed for 3270 terminals. Rather than requiring users to enter data in a 3270 terminal emulator session, a VA Smalltalk application can interact directly with the host application. From the host application's perspective, the VA Smalltalk application functions like a user at a 3270 terminal.
To communicate with host applications, VA Smalltalk uses the EHLLAPI, a feature provided by 3270 terminal emulators such as PComm V4.1.
You can configure the DLL name and entry point name used by VA Smalltalk to use your favorite emulator, as long as it conforms to HLLAPI. You must create a class method in the application's application class called startUp. The following example configures VA Smalltalk to use the IBM Communications Manager V2.1 emulator.
startup
Abt3270Hllapi dllName: 'acs3ehap'.
Abt3270Hllapi entryPointName: 'HLLAPI'.
AbtHllapiStructures wordBoundary: False.
Abt3270HllapiPMSubApp callingConvention: #c16.
For Windows:
For Windows, VA Smalltalk 3270 support provides methods supporting both the IBM and Attachmate EHLLAPI products. VA Smalltalk 3270 support assumes the IBM product by default. To switch between each of the vendor products, execute one of the following Smalltalk statements from the System Transcript window or a workspace: .
"Execute the following to switch from IBM support to Attachmate"
Abt3270HllapiWinSubApp selectAttachmate.
"Execute the following to switch from Attachmate support to IBM"
Abt3270HllapiWinSubApp selectIBM.
To communicate with 3270-based applications, VA Smalltalk uses the 3270 Screen part, located in the 3270 HLLAPI category on the parts palette. Each 3270 Screen part represents a specific host menu, panel, or other screen. To interact with multiple panels of a host application, you simply use multiple 3270 Screen parts, each set up for a different host panel.
Last modified date: 10/06/2020