Guardian Application Conversion Guide

Opening and Communicating With a High-PIN Server
Converting Pascal Applications
6–18 096047 Tandem Computers Incorporated
Opening a High-PIN Server for a Backup Requester Process
If your requester is running as a process pair, it might open the server for its backup
process using the CHECKOPEN procedure:
status := CHECKOPEN (server_name,
server_file_number,
nowait_depth,
sync_depth,
{ seq_block_buffer } ,
{ buffer_length } ,
back_error);
Figure 6-5 shows a requester process pair and a server process.
Figure 6-5. Opening a High-PIN Server for a Backup Process
$SRV
Server
Process
TACL
Pascal
Requester
Process Pair
$REQ
Primary
$REQ
Backup
Convert your requester to open the high-PIN server for its backup process using the
FILE_OPEN_CHKPT_ procedure. To identify the high-PIN server,
FILE_OPEN_CHKPT_ requires the file number returned by the FILE_OPEN_
procedure call in the primary process. The system returns a file-system error (if a file-
system error occurs) in the returned value error and the status of the backup open in
an output parameter, which is the backup_open_status parameter in this example:
error := FILE_OPEN_CHKPT_(server_file_number,
backup_open_status);
If you opened the server using the nowait open option, you must call the AWAITIO[X]
procedure to complete the open. To determine the error and
backup_open_status values, call the FILE_GETINFOLIST_ procedure and check
the items specified by ZSYS_VAL_FINF_LASTERROR and
ZSYS_VAL_FINF_LASTERRORDETAIL, respectively (provided you use the ZSYSPAS
file).