what is the storage class of a global variable ?

Question

If I write
 

#include<stdio.h>
int a;
main()
{
//code
}

then since a is a global variable so what is the storage class of it , is it extern ?

Comments

no, you don't have something like a default storage class for global variables in C programming. It always has a "static storage duration" which is not the same as "static storage class".

Refer here: https://stackoverflow.com/questions/3281925/what-is-default-storage-class-for-global-variables

Answer 1

No, it is of static storage class because you have also defined variable here.

If you have written extern int a;, then it would have been of extern storage class.

Ref: http://www.lix.polytechnique.fr/~liberti/public/computing/prog/c/C/CONCEPT/storage_class.html

Comments

But in c by default storage specifier is auto..static keyword is always explicitly written..plz explain

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Yes, it is extern by default.

http://stackoverflow.com/questions/4239834/global-variable-in-c-are-static-or-not

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It is of external linkage, but of static storage class.

Answer 2

in C ,by default global variable have extern  linkage

related  theory

Linkages of identifiers

3) If the declaration of a file scope identifier for an object or a function contains the storage-class specifier static, the identifier has internal linkage.

5) If the declaration of an identifier for a function has no storage-class specifier, its linkage is determined exactly as if it were declared with the storage-class specifier extern. If the declaration of an identifier for an object has file scope and no storage-class specifier, its linkage is external.