Interrupt 21h Function 4302h 

Obtains the compressed size, in bytes, of a given file or directory.

mov ax, 4302h            ; Get Compressed File Size

mov dx, seg PathName     ; see below

mov ds, dx

mov dx, offset PathName 

int 21h

jc error

Parameters

PathName

Address of a null-terminated string that specifies the file or directory to retrieve the file size for.

Return Value

Clears the carry flag if successful. Otherwise, the function sets the carry flag and sets the AX register to an error value.

Remarks

The function obtains the actual number of bytes of disk storage used to store the file. If the file is located on a volume that supports compression and the file is compressed, the value obtained is the compressed size of the specified file. If the file is not located on a volume that supports compression or if the file is not compressed, the value obtained is the file size, in bytes, rounded up to the nearest cluster boundary.