Function 5701h Set File Date and Time

mov bx, Handle ;handle of file

mov cx, FileTime ;new file time

mov dx, FileDate ;new file date

mov ax, 5701h ;Set Date and Time

int 21h

jc error_handler ;carry set means error

Set File Date and Time (Function 5701h) sets the time and date for a file, replacing the time and date set for the file when it was last modified.

Parameters

Handle

Identifies the file to set the date and time for.

FileTime

Specifies the new time for the file. The file time is a 16-bit value with the following format:

Bits

Contents

0–4	Second divided by 2
5–10	Minute (0–59)
11–15	Hour (0–23 on a 24-hour clock)

FileDate

Specifies the new date for the file. The file date is a 16-bit value with the following format:

Bits

Contents

0–4	Day of the month (1–31)
5–8	Month (1 = January, 2 = February, etc.)
9–15	Year offset from 1980 (add 1980 to get actual year)

Return Value

If the function is successful, the carry flag is clear. Otherwise, the carry flag is set and the AX register contains an error value, which may be 0006h (ERROR_INVALID_HANDLE).