bright@dataioDataio.UUCP (Walter Bright) (02/02/86)
Anyone out there know a way to truncate a file to 'n' bytes in length (without going in and directly manipulating the FAT)? I need a method that is 'well-behaved'. Thanks in advance.
rde@ukc.UUCP (02/04/86)
In article <901@dataioDataio.UUCP> bright@dataio.UUCP writes: >Anyone out there know a way to truncate a file to 'n' bytes in >length (without going in and directly manipulating the FAT)? I >need a method that is 'well-behaved'. > Use function 42H (seek) to move the file pointer to the place you want the file truncated. Then use function 40H (write) with a count of zero (CX=0). This comes from the MS-DOS Programmer's Manual so it ought (!) to be well behaved. Hope this helps. -- Bob Eager rde@ukc.UUCP rde@ukc ...!mcvax!ukc!rde Phone: +44 227 66822 ext 7589
bill@hp-pcd.UUCP (02/05/86)
Truncating a file to 'n' bytes is fairly easy:
[1] Open the file for read/write access using Int 21h function 3Dh.
[2] Use Int 21h function 42h to position the file pointer to position 'n'.
[3] Truncate the file at that point by using Int 21h function 40h (Write
to File or Device) with a byte count of zero in CX.
[4] Close the file using Int 21h function 3Eh (or 4Ch).
bill frolik
hplabs!hp-pcd!bill