Typedef structure's member being static or not in c-CodePudding

I think this none sense doesnt that? because after creating instance from that variable. It will initialize that variable whole, will not behave differently to members an will initialize all of them, doesn't that? As I know static variables are global variable but their usage are restricted to specified function or source file.

typedef struct
{
    const uint32_t mainpointer;
    static uint32_t currentpointer;    
    uint16_t num_el;    
    uint8_t num_byte;    
}arrayPushCirc_doublebuffer_instance;

void main(void)
{
arrayPushCirc_doublebuffer_instance struction;
function1(struction);
}

CodePudding user response：

In C data members of a structure may not have storage class specifiers.

So this declaration of a data member

static uint32_t currentpointer;

is invalid in C.

According to the C Grammar data member declarations may have only the following specifiers

specifier-qualifier-list:
    type-specifier specifier-qualifier-listopt
    type-qualifier specifier-qualifier-listopt

On the other hand, you may use the storage class specifier static for declarations of objects in the file scope or a function scope.

For example

#include <stdint.h>

typedef struct
{
    const uint32_t mainpointer;
    uint32_t currentpointer;    
    uint16_t num_el;    
    uint8_t num_byte;    
}arrayPushCirc_doublebuffer_instance;

static arrayPushCirc_doublebuffer_instance struction; 

int main( void )
{
    //...
}

Pay attention to that according to the C Standard the function main without parameters shall be declared like

int main( void )