test.c

#include <xcb/xcb.h>
#include <stdio.h>
#include <stdbool.h>


struct area1_t {
    unsigned int begin:16;
    unsigned int end:16;
    bool active:1;
    int align:3;
    int button:3;
    xcb_window_t window;
    char *cmd;
};

struct area2_t {
    unsigned int begin:16;
    unsigned int end:16;
    bool active:1;
    int align:3;
    int button;
    xcb_window_t window;
    char *cmd;
};

struct area3_t {
    uint16_t begin;
    uint16_t end;
    bool active;
    int8_t align;
    xcb_button_t button;
    xcb_window_t window;
    char *cmd;
};

int main(int argc, char** argv) {
    printf("%ld\n", sizeof(struct area1_t));
    printf("%ld\n", sizeof(struct area2_t));
    printf("%ld\n", sizeof(struct area3_t));
}