Category: DOS kernel
INT 21 - DOS 1+ - FIND FIRST MATCHING FILE USING FCB AH = 11h DS:DX -> unopened FCB (see #01345), may contain '?' wildcards Return: AL = status 00h successful [DTA] unopened FCB for first matching file FFh no matching filename, or bad FCB Notes: the type of the returned FCB depends on whether the input FCB was a normal or an extended FCB the data returned in the DTA (disk transfer area) is actually the drive number (or extended FCB header and drive number) followed by the file's directory entry (see #01352); this format happens to be compatible with an unopened FCB for extended FCBs with search attribute 08h, the volume label (if any) will be returned even if the current directory is not the root dir. DOS 3.0+ also allows the '*' wildcard the search FCB at DS:DX must not be modified if AH=12h will be used to continue searching; DOS 3.3 has set the following parts of the FCB: 0Ch BYTE ??? 0Dh WORD directory entry number of matching file 0Fh WORD cluster number of current directory 11h 4 BYTEs ??? 15h BYTE drive number (1=A:) this function is used by many copy protection schemes to obtain the starting cluster of a file BUG: under Windows95, if a .EXE program ("MZ" header) rather than a true .COM calls this function from a DOS box, the ten bytes of the directory entry from 0Ch to 15h may be filled with zeros rather than the additional file times SeeAlso: AH=12h,AH=1Ah,AH=4Eh,INT 2F/AX=111Bh