FT_BITCLR()
 Clear (reset) selected bit in a byte
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 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.

 Source: BITCLR.PRG

 Author: Forest Belt, Computer Diagnostic Services, Inc.