What exactly does the static keyword do in C? I have seen it used in several diverse contexts:

1) As a variable outside a function:

#include <stdio.h>

static int x = 5;
int main (void)
{
  printf("%d\n", x);
}

2) As a variable inside a function:

void func (void)
{
  static int count=0;
  printf("%d\n", count++);
}

3) As part of a function declaration/definition:

static void func (void);

4) As part of a function parameter list containing an array:

void func (int arr[static 5]);

All of these uses seem quite unrelated. What exactly is the purpose of static in all the above examples?

posted about 3 years ago

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Lundin‭

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