Gcc: accessing and initializing unions and bitfields within a struct
I have a structure consisting of union, variable and 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 correct way to initialize it? I used
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 merge point is that I want to be able to assign values to either the client or the handler and let them use the same pointer. I've tried a few things and I know I can change the structure, but I just wanted to know if there is a way to initialize and access it in C99.
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2 answers
It might work. I think the trick is the name 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};
}
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