FLUSH

Writes all the buffers for a sequential I/O file immediately. Normally, sequential I/O uses buffering for input/output operations, and writes are not immediately flushed.

COMMAND SYNTAX

    FLUSH file.variable { THEN statements [ ELSE statements ] | ELSE statements }

file.variable specifies a file previously opened for sequential processing. If file.variable evaluates to null, the FLUSH statement fails and the program enters the debugger. After the buffer is written to the file, it executes the THEN statements, ignoring the ELSE statements.

If none of the above can be completed, it executes the ELSE statements.

EXAMPLE

       dir_name = '.'
       file_name = 'report.txt'
       DELETESEQ dir_name, file_name ELSE NULL
       *
       OPENSEQ dir_name, file_name TO f_report ELSE NULL
       WRITESEQ 'New data' TO f_report ELSE NULL
       *
       FLUSH f_report ELSE NULL
       CRT '<' : DIR(file_name)<1> : '>'     ;* 9

NOTE

For prime emulation FLUSH in this example will fail if there were still no WRITESEQs since file isn't created immediately on OPENSEQ:

       dir_name = '.'
       file_name = 'report.txt'
       DELETESEQ dir_name, file_name ELSE NULL
       *
       OPENSEQ dir_name, file_name TO f_report ELSE NULL
       *
       FLUSH f_report ELSE NULL
       CRT '<' : DIR(file_name)<1> : '>'     ;* 0

This program will crash with the following message:

     ∗∗ Error [ NOT_FILE_VAR ] ∗∗
     Variable is not an opened file descriptor , Line     7 , Source test.b
     Trap from an error message, error message name = NOT_FILE_VAR

Under seq emulation program will not crash.