putting a structure in shared memory *Unix*

How would I copy a structure into shared memory on Unix? The structure is below:

Code:

      struct sh_weather {
    
          float intemp_F; // indoor temperature in Fahrenheit
          float intemp_C; // indoor temperature in Celsius
          float outtemp_F; // Outdoor temperature in Fahrenheit
          float outtemp_C; // outdoor temp in Celsius 
          unchar w_speed; // Wind Speed in MPH
          char *wind_d; // String pointing to wind direction buffer
          float inbaro; // Inches of Mercury
          float mmbaro; // Mercury in MM
          unchar out_hum; // Outside Humidity
          unchar in_hum;  // Inside Humidity
          float t_rain;  // Total rain since weather system reset
      } share_weather;

struct share_weather *weatherPTR ; // point to the shared weather structure



do I use mmap()?

also how do I typedef a pointer to the structure to update the data fields inside it

I got a shared memory chunk with this:

Code:

      shm_id = shmget(key, sizeof(share_data), IPC_CREAT | 0644); //  Give only Read permission to Clients
            if (shm_id < 0) {
         printf("Problem getting shared memory segment using key %d\n", key);
         exit(1);
            }

kinda lost after that
thanks

Code:

memcpy(pointer_to_shared_memory, pointer_to_struct_you_want_to_share, sizeof(struct_you_want_to_share));

>> char *wind_d; // String pointing to wind direction buffer
That buffer will also need to be in shared memory.

>> kinda lost after that
You need to call shmat() as well.
Shared Memory Segments

gg

I usually use

shm_open()
ftruncate()
mmap()

sequence. You propably will also need sem_open, sem_wait and sem_post to synchronize the access to shm. You propably do not want clients being reading the data at the same time you're updating it.