Processing Begin or End of File Structured Fields

When the Begin or End of File structured fields are used with brackets or timeout intervals, the Begin or End of File SFs take precedence over the brackets or timeout intervals in determining when a print job begins or ends. See the following examples:

Begin or End of File structured fields overriding brackets:
```
Begin Bracket, Begin of File Structured Field, ...Data...,
End Bracket
```
The device will wait indefinitely until the End of File structured field is received before ending the print job.
Begin or End of File structured fields overriding timeout intervals:
```
Begin of File structured fields, ...Data..., pause > timeout value
```
The device will wait indefinitely until the End of File structured fields is received before ending the print job.
Inconsistent use of Begin or End of File structured fields and brackets:
```
Begin Bracket, ...Data1...,
Begin of File Structured Fields,...Data2..,
End of File Structured Fields, ...Data3...,
End Bracket
```
When you use the Begin of File and End of File structured fields inconsistently with brackets, the results are unpredictable. In the preceding example, the device might process Data1, Data2, and Data3 as separate jobs or combine two or more of them into one file.

For predictable results, each data block must be enclosed by a Begin of File structured field and an End of File structured field. The following example shows three print jobs all delimited by Begin or End of File structured fields:

Begin Bracket, Begin of File Structured Field, ...Data1...,
End of File Structured Field,(job1)
Begin of File Structured Field, ...Data2..., End of File Structured Field, (job2)
Begin of File Structured Field, ...Data3..., End of File Structured Field,
End Bracket(job3)

PC/3270 always keeps track of brackets and timeout intervals. After the emulator receives a Begin of File structured field, it takes no action on Begin Brackets, End Brackets, or timeout until it receives an End of File structured field. After a valid End of File SF is processed, the emulator defaults to delimiting jobs by brackets or timeout intervals until it receives the next Begin of File structured field.