Magic number (programming)

In computer programming, a magic number is any of the following:

• A unique value with unexplained meaning or multiple occurrences which could (preferably) be replaced with a named constant
• A constant numerical or text value used to identify a file format or protocol (for files, see List of file signatures)
• A distinctive unique value that is unlikely to be mistaken for other meanings (e.g., Globally Unique Identifiers)