Int 21 Fn 67  - Dos 3.3+ - Set Handle Count                                [D]

   AH = 67h
   BX = size of new file handle table for process

Return: CF clear if successful
   CF set on error
       AX = error code (see #1366 at AH=59h/BX=0000h)
Desc:  adjust the size of the per-process open file table, thus raising or
     lowering the limit on the number of files the caller can open
     simultaneously

Notes: if BX <= 20, no action is taken if the handle limit has not yet been
     increased, and the table is copied back into the PSP if the limit
     is currently > 20 handles
   for file handle tables of > 20 handles, DOS 3.30 never reuses the
     same memory block, even if the limit is being reduced; this can lead
     to memory fragmentation as a new block is allocated and the existing
     one freed
   only the first 20 handles are copied to child processes in DOS 3.3-6.0
   increasing the file handles here will not, in general, increase the
     number of files that can be opened using the runtime library of a
     high-level language such as C
   Novell DOS 7 reportedly terminates the calling program if the JFT is
     being reduced in size and there are any open file handles beyond
     the portion of the JFT being retained
BUGS:  the original release of DOS 3.30 allocates a full 64K for the handle
     table on requests for an even number of handles
   DR DOS 3.41 and 5.0 will lose track of any open file handles beyond
     the portion of the JFT retained after the call; MS-DOS will indicate
     error 04h if any of the JFT entries to be removed are open

See Also: AH=26h,AH=86h