C anonymous inner struct initialization

struct_init.c

#include <stdio.h>

typedef struct {
    // Required
    const char *fq_name[3];

    // Optional
    const char *display_name;
    const char *href;
    const char *name;
    const char *uuid;

    struct {
        const char *fq_name[3];
        struct {
            struct {
                struct {
                    const char *ip_prefix;
                    int ip_prefix_length;
                } subnet;
                struct {
                    const char *start;
                    const char *end;
                } allocation_pools [1];
                const char *default_gateway;
                const char *dns_server_address;
            } subnets[1];
        } attributes;
    } network_ipams[1];
} VirtualNetwork;

int main() {
    VirtualNetwork vnet = {
        .fq_name = {"domain", "project", "test-net"},

        .display_name = "Test network",
        .href = NULL,
        .name = NULL,
        .uuid = NULL,

        .network_ipams = {
            {
                .fq_name = {"domain", "project", "ipam"},
                .attributes = {
                    {
                        {
                            .subnet = {"10.1.0.0", 16},
                            .allocation_pools = {{"10.1.0.2", "10.1.255.254"}},
                            .default_gateway = "10.1.0.1",
                            .dns_server_address = "10.1.0.2"
                        }
                    }
                }
            }
        }
    };
    
    printf(
        "First IP address = %s/%i\n",
        vnet.network_ipams[0].attributes.subnets[0].allocation_pools[0].start,
        vnet.network_ipams[0].attributes.subnets[0].subnet.ip_prefix_length
    );
}