SPUG: C question ;)

Benjamin Franks benjamin at dzhan.com
Sun Mar 10 19:35:38 CST 2002

woops!  I fat-fingered that email way too soon.  sorry for the confusion.
anyway, here should be a more complete question. ;)

I know this is a perl list, but I've had such good success with my
questions in the past, I though I'd throw out a C question.

I'd like to tie an array of structures to shared memory.  But I have
questions about accessing the elements.

So for a simple example, say I have:

typdef struct {
  time_t	a;
  time_t	b;
} my_struct;

and I create a shared memory segment with size to store 1000 of these
structs, as in:

int shmid=shmget((ftok("blah/blah",1), 1000*sizeof(my_struct), IPC_CREAT | 0666);

Then when I attach the shmid to a pointer, do I want to attach a pointer
of the my_struct type, as in:

my_struct *ptr;

I guess that's where my confusion lies.  Let's say I want to work on the
500th element of my shared memory array of my_struct's.  How can I do it?


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