magic-numbers

How can I create a reserved pointer value? The context is this: I have been thinking of how to implement a data structure for a dynamic scripting language (I am not planning on implementing this - just wondering how it would be done). Strings may contain arbitrary bytes, including NUL. Thus, it is necessary to store the value separately. This requires a pointer (to point to the array) and a number. The first trick is that if the pointer is NULL, it cannot possibly be a valid string, so the number can be used for an actual integer. If a second reserved pointer value could be created, this could

This question was migrated from Information Security Stack Exchange because it can be answered on Stack Overflow. Migrated 6 years ago . Files are categorized by file-extension. So my question is, how to identify the file type even the file extension has been changed. For example, i have a video file with name myVideo.mp4 , i have changed it to myVideo.txt . So if i double-click it, the preferred text editor will open the file, and won't open the exact content. But, if i play myVideo.txt in a video player, the video will be played without any problem. I was just thinking of developing an

This is a number that's returned as an exit code in many .NET exceptions (particularly COM exceptions, I think). In this question someone used Reflector to find out that this value was initialized to a private variable in nearly every Exception constructor. My question is, why? What significance does this number have? It's hard to believe that it was chosen arbitrarily. I don't even see any numeric significance (e.g., in its binary or hex representation). Did you pay attention to its hex representation, E0434F4D ? Here's a brief synopsis: E0 - represents E 43 - ASCII for C 4F - ASCII for O 4D

An SVG file is basically an XML file so I could use the string <?xml (or the hex representation: '3c 3f 78 6d 6c' ) as a magic number but there are a few opposing reason not to do that if for example there are extra white-spaces it could break this check. The other images I need/expect to check are all binaries and have magic numbers. How can I fast check if the file is an SVG format without using the extension eventually using Python? XML is not required to start with the <?xml preamble, so testing for that prefix is not a good detection technique — not to mention that it would identify every