Because the code uses !=, not ==; so the first comparison tests whether (SearchFlags & (int) AttributeSearchFlags.Index) is equal to zero; and the second tests whether the result of that comparison is false.
-----Original Message----- From: Moderated discussion of advanced .NET topics. [mailto:[EMAIL PROTECTED] On Behalf Of Simon Hewitt Sent: Thursday, 27 February 2003 8:02 PM To: [EMAIL PROTECTED] Subject: [ADVANCED-DOTNET] Compilation question.... Given this source code C# source: public bool IsIndexed { get { return (SearchFlags & (int) AttributeSearchFlags.Index) != 0; } } why is the comparison to 0 done twice? Anakrino decompilation: public bool get_IsIndexed() { return this.SearchFlags & 1 == 0 == 0; } ILDASM decompilation: { // Code size 15 (0xf) .maxstack 2 IL_0000: ldarg.0 IL_0001: call instance int32 SimmoTech.ActiveDirectory.ADAttributeSchema::get_SearchFlags() IL_0006: ldc.i4.1 IL_0007: and IL_0008: ldc.i4.0 IL_0009: ceq IL_000b: ldc.i4.0 IL_000c: ceq IL_000e: ret } // end of method ADAttributeSchema::get_IsIndexed
