Logical XOR operator

Introduction

Occasionally I come to a need of a logical xor operator (^^) that, obviously, doesn't exist in C++. However, it can be rather easily implemented.

Code listing

#define log_xor || log_xor_helper() ||


struct log_xor_helper {
    bool value;
};

template<typename LEFT>
log_xor_helper &operator ||(const LEFT &left, log_xor_helper &xor) {
    xor.value = (bool)left;
    return xor;
}

template<typename RIGHT>
bool operator ||(const log_xor_helper &xor, const RIGHT &right) {
    return xor.value ^ (bool)right;
}

Examples

0 log_xor 0 == false
0 log_xor 5 == true
8 log_xor 0 == true
8 log_xor 5 == false

Other details

• Although they don't have to have the same type, operands should be castable into a simple boolean.
• Precedence of log_xor operator is the same as logical or's (||) one.
• If you decide to use it, I suggest you to add log_xor keyword to the usertype.dat file and insert somewhere the #pragma warning(disable: 4800) line.