In the C programming language, an external variable is a variable defined outside any function block. On the other hand, a local (automatic) variable is a variable defined inside a function block.
As an alternative to automatic variables, it is possible to define variables that are external to all functions, that is, variables that can be accessed by name by any function. (This mechanism is rather like Fortran COMMON or Pascal variables declared in the outermost block.) Because external variables are globally accessible, they can be used instead of argument lists to communicate data between functions. Furthermore, because external variables remain in existence permanently, rather than appearing and disappearing as functions are called and exited, they retain their values even after the functions that set them have returned. —The C Programming LanguageRead more about External Variable: Definition, Declaration and The extern Keyword, Scope, Lifetime and The static Keyword, Example (C Programming Language)
Famous quotes containing the words external and/or variable:
“The law is only one of several imperfect and more or less external ways of defending what is better in life against what is worse. By itself, the law can never create anything better.... Establishing respect for the law does not automatically ensure a better life for that, after all, is a job for people and not for laws and institutions.”
—Václav Havel (b. 1936)
“There is not so variable a thing in nature as a lady’s head-dress.”
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