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ESL Documentation

Field-Oriented Screens

The 5250 screen buffer contains 24 lines by 80 columns and is generally field-oriented (formatted), or organized by fields.

The 3270 screen buffer can have different display models:

 

Mod Number

Screen Size

Mod 2

24 x 80

Mod 3

32 x 80

Mod 4

43 x 80

Mod 5

27 x 132

 

Most of the ECS subroutines are written to access field-oriented screens.  accesses the screen buffer by first assigning sequential numbers to each field in the buffer. By specifying a field number, you can retrieve that field's contents and associated attributes, or write text into the specified field.

Line-Oriented Screens

Sometimes, a 3270/5250 application contains screens in which each line is a field of its own, or contains screens that have no fields at all. These are called line-oriented (unformatted) screens.

There are two ECS subroutines used to access line-oriented screens:

EcsReadLine

EcsGetLastNonBlankLineNumber

You can use these subroutines to access line-oriented or field-oriented screens, but you cannot use field-oriented subroutines to access line-oriented screens.