$FUNCNAME$
   FT_BITCLR()
$CATEGORY$
   String
$ONELINER$
   Clear (reset) selected bit in a byte
$SYNTAX$
   FT_BITCLR( <cByte>, <nBitPos> ) --> cByte
$ARGUMENTS$
   <cByte> is a character from CHR(0) to CHR(255).

   <nBitPos> is a number from 0 to 7 conforming to standard
   right-to-left bit numbering convention and representing the
   position of the bit within the byte.
$RETURNS$
   Returns new byte, with designated bit cleared (reset).
   If parameters are faulty, returns NIL.
$DESCRIPTION$
   In effect, ANDs argument byte with a byte that has all bits set except
   the target bit.  If bit is already clear (0), it remains clear.
   Note: Calls FT_ISBIT() which is also in this Library.

   This function is presented to illustrate that bit-wise operations
   are possible with Clipper code.  For greater speed, write .C or
   .ASM versions and use the Clipper Extend system.
$EXAMPLES$
   This code would clear bit 4 in a byte represented by CHR(115):

     cNewByte := FT_BITCLR( CHR(115), 4 )
     ? ASC( cNewbyte )         // result: 99
     ? cNewByte                // result: 'c'

   This code would clear bit 5 in the byte represented by letter 'A':

     FT_BITCLR( 'A', 5 )       // result: 'A', since
			       // bit 5 already clear

   For a demonstration of Clipper bit manipulations, compile and
   link the program BITTEST.PRG in the Nanforum Toolkit source code.
$SEEALSO$
   FT_BITSET(), FT_ISBIT()
$Author: itk $
   Forest Belt, Computer Diagnostic Services, Inc.
$end$

