Gcc: Accessing and initializing unions and bitfields within struct

Question

I have a struct that consists of a union, a variable and a bitfield:

typedef struct router_client {
    union {
        QHsm  *client;
        void (*handler)(QSignal sig, QParam par);
    };
    uint8_t level;
    struct {
        uint8_t presence:2;
        uint8_t is_hsm:1;
        uint8_t is_handler:1;
    };
} router_client_t;

What is the proper way to initialize it? I used to

router_client_t = {.client=(QHsm*)&qhsm_foo, level = l, \
.presence = p, .is_hsm = s, .is_handler = a}

But when switching toolchain from Code Red MCU tools to Cross GCC I started getting

unknown field 'client' specified in initializer
unknown field 'presence' specified in initializer
...

The point of the union is that I want to be able to assign values either to client or handler and let them share the same pointer. I tried a few things and I know I can change the struct but I just wanted to know if there is a C99 way of initializing and accessing it.

Answer 1

This can work. I think that the trick is name of structs and union.

typedef union {
    int  *client;
    void (*handler)(int sig, int par);
}union_t;

typedef struct {
    uint8_t presence:2;
    uint8_t is_hsm:1;
    uint8_t is_handler:1;
}struct_t;

typedef struct router_client {
    union_t test;
    uint8_t level;
    struct_t test2
} router_client_t;

void main()
{
    int pippo;
    router_client_t pippo2= {.test.client=(int*)&pippo, .level = 10, .test2.presence = 2, .test2.is_hsm = 1, .test2.is_handler = 1};
}

Or as you wrote:

#include <stdint.h>

typedef struct router_client {
    union{
        int  *client;
        void (*handler)(int sig, int par);
    }union_t;
    uint8_t level;
    struct {
        uint8_t presence:2;
        uint8_t is_hsm:1;
        uint8_t is_handler:1;
    }struct_t;
} router_client_t;

void main()
{
    int pippo;
    router_client_t pippo2= {.union_t.client=(int*)&pippo, .level = 10, .struct_t.presence = 2, .struct_t.is_hsm = 1, .struct_t.is_handler = 1};
}