home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Loadstar 8
/
008.d81
/
dos #18
< prev
next >
Wrap
Text File
|
2022-08-26
|
1KB
|
67 lines
DOS and DON'Ts -- Part 18
by Joel Ellis Rea
This month we will discuss some ad-
vanced SEQuential file handling, in-
cluding an undocumented OPEN mode!
The undocumented OPEN mode param-
eter is ,A for APPEND. The ,A param-
eter tells DOS that you want to OPEN
an existing file, but that you want to
WRITE data to it, not READ data from
it. The ,A parameter tells DOS
that all new data will be written to
the END of the file, instead of the
BEGINNING. In other words, DOS is
told to APPEND new data to the END of
an ALREADY EXISTING file! This saves
having to OPEN the existing file for
READ, OPENing a dummy file for WRITE,
copying every character from the READ
file to the dummy file, CLOSING the
READ file and Deleting the READ file,
before you can WRITE the new data. You
would then have to CLOSE the DUMMY
file, then RENAME the DUMMY file to
the name of the old, now deleted READ
file! (AND you would have to hope you
had enough free space on the disk to
hold a copy of an existing file!). The
,A(PPEND) parameter saves you that
trouble, and enables you to add new
data automatically.
------- Continued in Part 19 ---------