static -- C Keyword

Declare storage class

static  is a  C storage  class.   It has  two entirely  different meanings,
depending upon whether it appears inside or outside a function.

Outside a function, static means  that the function or variable it preceeds
may not be seen outside the module.

Inside a function, static may only  precede a variable.  It means that that
variable is permanently allocated,  rather than allocated on the stack when
the function is entered and discarded when the function exits.  If a static
variable is initialized, that  occurs before the program starts rather than
every time the  function is entered.  If a function  returns a pointer to a
variable, often that variable is declared static within the function.  If a
pointer to a non-static local  variable is returned, that variable is freed
when  the  function  returns  and  the  pointer points  to  an  unprotected
location.

Example

The  following example  demonstrates the  uses of  the static  keyword.  It
returns the next integer in a sequence as a string.

/* static to keep function hidden outside of this module */
static char *nextInt()
{
    /* static to protect value between calls */
    static int next = 0;
    /* static to allow the return of a pointer to s */
    static char s[5];

    sprintf(s, "%d", next++);
    return(s);
}

See Also

auto,
C keywords,
extern,
register variable,
storage class
ANSI Standard, §6.5.1

© 2012 by Stephen A. Ness