Guardian Programmer's Guide

Communicating With Disk Files
Guardian Programmer’s Guide — 421922-014
5 - 65
Key-Sequenced File Programming Example
!------------------------------------------------------------
! Procedure to process an invalid command. The procedure
! informs the user that the selection was other than "r,"
! "u", "a," or "x."
!------------------------------------------------------------
PROC INVALID^COMMAND;
BEGIN
PRINT^BLANK;
! Inform the user that his selection was invalid
! then return to prompt again for a valid function:
PRINT^STR("INVALID COMMAND: " &
"Type either 'r,' 'u,' 'i,' or 'x'");
END;
!------------------------------------------------------------
! This procedure does the initialization for the program.
! It calls INITIALIZER to dispose of the startup messages.
! It opens the home terminal and the data file used by the
! program.
!------------------------------------------------------------
PROC INIT;
BEGIN
STRING .PARTFILE^NAME[0:MAXFLEN - 1]; !name of part file
INT PARTFILE^LEN; !length of part-file
! name
STRING .TERMNAME[0:MAXFLEN - 1]; !terminal file
INT TERMLEN; !length of terminal-
! file name
INT ERROR;
! Read and discard startup messages.
CALL INITIALIZER;
! Open the terminal file. For simplicity we use the home
! terminal; the recommended approach is to use the IN file
! read from the Startup message; see Section 8, Communicating
With a TACL Process for
! details:
CALL PROCESS_GETINFO_(!process^handle!,
!file^name:maxlen!,
!file^name^len!,
!priority!,
!moms^processhandle!,
TERMNAME:MAXFLEN,
TERMLEN);
ERROR := FILE_OPEN_(TERMNAME:TERMLEN,TERMNUM);
IF ERROR <> 0 THEN CALL PROCESS_STOP_;