bit_field_minimum_size

bit_fields_size.c

#include <stdio.h>

struct withshort
{
    short c : 4;
    short c2 : 4;
    short c3 : 1;
    short c4 : 7;
};

struct withint
{
    int c : 4;
    int c2 : 4;
    int c3 : 1;
    int c4 : 7;
};

struct withlong
{
    long c : 4;
    long c2 : 4;
    long c3 : 1;
    long c4 : 7;
};

int main()
{
    printf("withshort size = %zu\n", sizeof(struct withshort));
    printf("withint   size = %zu\n", sizeof(struct withint));
    printf("withlong  size = %zu\n", sizeof(struct withlong));

    return 0;
}

output.txt

withshort size = 2
withint   size = 4
withlong  size = 8