Lifetime of "extern" variable in C?

Question

What is the lifetime of variable p if it is declared as extern int p;

Is it static, dynamic, automatic or it has no lifetime because there is no linkage?

Answer 1

or it has no lifetime because there is no linkage?

The keyword extern means a variable is only declared, that is no storage is allocated for it [1].

The keyword extern has got nothing to do with the life time of a variable. That said, the life time/scope of a variable depends only on where exactly it occurs in the code.

Note

[1] When extern is used with an assignment like

extern int i=5; 

the keyword extern is ignored and the usual scope rules apply to the variable

[2] Please check my other [ answer ] on this.

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^{Interesing: As Stephen Prata in his book C++ Primer Plus puts it, the keyword extern means "Use the variable by this name previously defined externally"}