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The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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;* UniqueFile - Creates and opens a new file with a name unique to the
;* specified directory. The name is manufactured from the current time,
;* making it useful for temporary files. For DOS versions 3.0 and higher.
;*
;* Shows:   DOS Function - 5Ah (Create Temporary File)
;*
;* Params:  Attr - Attribute code (see header comments for CreateFile)
;*          Pspec - Pointer to ASCIIZ path specification
;*
;* Return:  Short integer with file handle or -1 for error
 
UniqueFile PROC USES ds,
        Attr:WORD,
        Pspec:PBYTE
 
        ; Get DOS version
        INVOKE  GetVer
 
        cmp     ax, 300                 ; 3.0 or higher?
        jb      e_exit                  ; No?  Quit with error
        LoadPtr ds, dx, Pspec           ; Point DS:DX to path spec
        mov     cx, Attr                ; CX = attribute
        mov     ah, 5Ah                 ; AH = function number
        int     21h                     ; Create Temporary File
        .IF     carry?
e_exit: mov     ax, -1                  ; Set error code
        .ENDIF
        ret
 
UniqueFile ENDP
                                    -♦-