Functions and Directives Functions and Directives

Function BXOr() Foundation

Calculates the result of a bitwise XOR operation.

Syntax
BXOr( <nVa1>, <nVal2>, [<nVal3>,...] ) -> nBitwiseXOr
Parameters
<nVal1>
<nVal1> is a numeric expression that is used as the first operand for the bitwise XOR operation.
<nVal2>
<nVal2> is a numeric expression that is used as the second operand. The parameter may be followed by an arbitrary number of additional operands.
Return

BXOr() returns the result of a bitwise exclusive-OR operation between operands <nVal1> and <nVal2>. If additional parameters are passed, another bitwise XOR operation is performed for each parameter. Once all parameters are processed, BXOr() returns the combined result of the XOR operation.

Description

BXOr() is a numeric function that performs a bitwise exclusive-OR operation between two or more operands. A bitwise XOR turns on all bits in the result that have a corresponding bit set in one but not in both operands. The following table illustrates this correlation.

Results produced by a bitwise XOR operation
Operand 1 Operand 2 Result
0 0 0
1 0 1
0 1 1
1 1 0

Bitwise operations are usually used with flag values, where a certain bit pattern represents a certain option being enabled or disabled. Using the function BXOr(), an individual option can easily be removed (disabled) from the flag value.

Examples
BXOr() 
// The example illustrates an exemplary usage of function BXOr() 

#define OPTION_1     1 
#define OPTION_2     2 
#define OPTION_3     4 

#define DEFAULTS     OPTION_1 + OPTION_2 + OPTION_3 

PROCEDURE Main() 

 LOCAL nSetting := DEFAULTS 

   nSetting := RemOption( nSetting, OPTION_2 ) 
   ? nSetting             // Result: 5 (OPTION_1 + OPTION_3) 
   nSetting := RemOption( nSetting, OPTION_3 ) 
   ? nSetting             // Result: 1 (OPTION_1) 

   WAIT "Done." 

RETURN 

// Remove option 'nOption' from the 
// value passed 
FUNCTION RemOption( nValue, nOption ) 
RETURN BXOr(nValue, nOption)
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