An additional type of magic quantity, although, is Employed in file formats. It is really just a price provided as normally the very first thing during the file which assists recognize the file structure, the version of the file format and/or perhaps the endian-ness of The actual file.

For example, they may insert non-typical code that ensures far better mistake messages, or perhaps operates all over some flaw inside their compiler, or maybe permits special optimizations by utilizing more features of that specific compiler.

However, SO should have the capacity to stand by yourself even if the remainder of the Web disappears! By all usually means website link to another resource, but I prefer to set some meat in the answer in addition.

The time period "magic variety" will get abused a little, nevertheless, referring to Just about everything that identifies a file format - including pretty prolonged ASCII strings inside the header.

Right after tests most options devoid of altering the source-code, I discovered the subsequent to acquire python-magic Performing out from the box:

As a result, we discover magic figures by measuring the flexibility of the code reader to understand, be very clear, and understand the meaning and objective of the essential benefit from its surrounding context. The significantly less acknowledged, considerably less crystal clear, and much more perplexed the reader is, the greater "magic" The essential worth is.

What If you'd like accessing your mock for a container object to get an error -- you do not need that to work? If every single mock has automatically acquired every protocol approach, then it results in being Significantly more challenging to do that. And also, MagicMock does a number of this preconfiguring for yourself, setting return values that may not be proper, so I assumed it would be far better to obtain this advantage one that has almost everything preconfigured and obtainable for you, but You may also have a everyday mock object and just configure the magic approaches you ought to exist...

I'm not specifically serious about the technical specifics, but typically in how I brought on it And the way I am able to prevent it Later on. This is some notes on the specific situation:

– mtvec Commented Aug 26, 2010 at 13:04 three properly, People are not in the current version of the standard. They are scheduled for inclusion in C++0x (and promptly skimming the draft didn't generate any data on how they might be applied, so you may well be suitable that they call for compiler magic to implement -- Conversely, their only goal then is to show this compiler magic so normal developers may well use it. They don't retain it to themselves like @Occupation's Java illustrations do.)

Because of this it really is unattainable to create an implementation of the Object and String classes in pure(*) Java. Now this is what I necessarily mean with "magic": to help make an implementation of such lessons, you will want some Specific assistance in magician the compiler.

std::initializer_list demands compiler guidance and can't be reimplemented as A further course (in terms of I'm sure), nevertheless I'm not sure if it counts since it's in c++0x.

I have normally used the time period "magic selection" in another way, being an obscure value stored inside a knowledge framework which may be confirmed as A fast validity Look at. By way of example gzip documents include 0x1f8b08 as their 1st three bytes, Java class documents begin with 0xcafebabe, and so on.

I'm hoping to install python-magic for Home windows and I've adopted the many Guidance in and recurring the process several occasions but I am continue to having this mistake:

Magic numbers are Exclusive worth of sure variables which triggers This system to behave in an Particular manner.