C#

CSHARP.STRUCT.BW.OR : Bitwise OR on Boolean (C#)

Summary

There is a suspicious use of | instead of ||.

C# has a bitwise and a logical-AND operation on Booleans, that is, & and &&. Similarly, C# has a bitwise and a logical-OR operation | and ||. The difference is that the logical operations have a short circuit semantics, that is, if the evaluation of the left-hand side is enough to determine the outcome of the operation, then the right-hand side is not evaluated; the bitwise operations, instead, evaluate both sides, always, which might be incorrect is most cases, or at least inefficient.

Properties

Class Name Bitwise OR on Boolean (C#)
Significance reliability
Mnemonic CSHARP.STRUCT.BW.OR
Categories
CWE CWE:768 Incorrect Short Circuit Evaluation
Availability Available for C# only.
Enabling Checks for this warning class are enabled by default. To disable them, add the following WARNING_FILTER rule to the project configuration file. 
WARNING_FILTER += discard class="Bitwise OR on Boolean (C#)"

Example 

using System;

namespace DocumentationExamples
{

    
    public class ShortCircuit
    {
        public static void Main(string[] args)
        {
            if (args.Length == 0 | IsOption(args[0])) // "Bitwise OR on Boolean (C#)" warning issued here
                Console.WriteLine("option expected");
            else
            {
                Console.WriteLine("ok");
            }
        }
        private static bool IsOption(string s)
        {
            return s.StartsWith("option");
        }
    }
}

In this example, the programmer should replace | with ||.

Resolution

Use the logical (short-circuit) version of the operators on Booleans.

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.