READ_WRITE

The application requires only read access to monitor the presentation space and allows other applications that perform read or write, or both, functions to share the presentation space. The application is also allowed to copy the presentation space and perform other read-only operations as usual.
Note: Sharing presentation space is not available between threads in a process.
Table 1. EHLLAPI Read and Write Sharing Option Combinations
Calling Application Super_Write Write_Super Write_Write Write_Read Write_None Read_Write
Super_Write Yes Yes Yes No No Yes
Write_Super (default) Yes No No No No No
Write_Write Yes No Yes No No Yes
Write_Read No No No No No Yes
Write_None No No No No No No
Read_Write Yes No Yes Yes No Yes

In addition to specifying compatible read and write access options, applications that are designed to work together but cannot allow others to work in the same presentation space can optionally define a keyword, KEY$nnnnnnnn, in the Set Session Parameters (9) function call. This keyword allows only those applications that use the same keyword to share the presentation space.

Note:
  1. The Start Keystroke Intercept (50) function is non-shareable. Only one application at a time can trap keystrokes.
  2. The Connect To Presentation Space (1) and Start Keystroke Intercept (50) functions share common subsystem functions. Successful requests by an application to share either of these functions can affect the requests of these two functions by other applications. For example, if application A successfully requests a Connect To Presentation Space (1) with Write_Read access and KEY$abcdefgh as the keyword, a request by application B to Connect To Presentation Space (1) or Start Keystroke Intercept (50) is successful only if both applications have set compatible read and write options.
Table 2. Prerequisite Functions and Associated Dependent Functions

Prerequisite Call

Functions

Access

Allocate Communications
Buffer (120)

Free Communication Buffer (120)

N/A

Connect Window
Service (101)

Change PS Window Name (106)
Change Switch List Name (105)
Disconnect Window
Service (102)
Query Window Service (103)
Window Status (104)


Write
Read
Query=Read
Set=Write
Write

Connect Presentation
Space (1)

Copy Field to String (34)
Copy OIA (13)
Copy Presentation Space (5)
Copy Presentation Space to String (8)
Copy Presentation Space to Clipboard (35)
Copy String to Field (33)
Copy String to Presentation Space (15)
Disconnect Presentation Space (2)
Find Field Length (32)
Find Field Position (31)
Query Cursor Location (7)
Query Field Attribute (14)
Paste Clipboard to Presentation Space (36)
Release (12)
Reserve (11)
Search Field (30)
Search Presentation Space (6)
Send key (3)
Set Cursor (40)
Start Playing Macro (110)
Wait (4)

Read
Read
Read
Read
Read
Write
Write
Write
Read
Read
Read
Read
Write
Write
Write
Read
Read
Read
Write
Write
Read

Connect Structured Field (120)

Disconnect Structured Field (121)
Get Request Completion (125)
Read Structured Field (126)
Write Structured Field (127)

N/A

Read Structured Field (126)

Get Request Completion (125)

N/A

Start Close Intercept (41)

Query Close Intercept (42)
Stop Close Intercept (43)

N/A

Start Host Notification (23)

Query Host Update (24)
Stop Host Notification (25)

Start Keystroke Intercept (50)

Get Key (51)
Post Intercept Status (52)
Stop Keystroke Intercept (53)
Send Key (3) if edit keystrokes are to
be sent (edit keystroked support is
available in Enhanced Mode)

N/A

Write Structured Field (127)

Get Request Completion (125)

N/A