Asynchronous Terminals and Printer Processes Programming Manual

PROCEDURE CALLS FOR ACCESSING TERMINALS
Transfer Termination When Reading
• System number of the I/O process
• Most significant word of the break tag
• Least significant word of the break tag
• Zero
The break tag is checkpointed by ATP6100 and TERMPROCESS to
their backup processes to satisfy the requirement for NonStop
operation.
TRANSFER TERMINATION WHEN READING
A READ or WRITEREAD from a terminal is terminated when any of the
following conditions is encountered:
• The application program issues a CANCELREQ procedure call.
• Interrupt character checking is enabled, and a line termina-
tion character is input from a conversational mode terminal.
On return from READ or WRITEREAD, the buffer contains the
number of characters returned in the count-read parameter, and
the condition code is CCE. The line termination character is
not included in count-read .
• Interrupt character checking is enabled, and an EOF is input
from a conversational mode terminal. On return from READ or
WRITEREAD, nothing is transferred into the buffer, the count-
read parameter is 0, and the condition code is CCG.
• Interrupt character checking is enabled, and a page termina-
tion character is input from a page mode terminal. On
return from READ or WRITEREAD, the buffer contains the number
of characters returned in the count-read parameter, and the
condition code is CCE. The page termination character is not
included in count-read .
• Interrupt character checking is enabled, and an application-
defined interrupt character is input. On return from READ
or WRITEREAD, the buffer contains the number of characters
returned in the count-read parameter, and the condition code
is CCE. The last character in the buffer is the interrupt
character.
• The number of characters entered equals the number of charac-
ters specified in the read-count parameter in the READ or
WRITEREAD request. On return from READ or WRITEREAD, the
buffer contains read-count characters, count-read equals read-
count , and the condition code is CCE.
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