Arrays of structs in shared mem

[bobbyjones01]

Hi,

I'm trying to store an array of structures in shared memory... and I can't figure out how to do it! I've done enough programming with shared memory in Unix that I *thought* I knew how it all worked (guess not) . So if anyone can give me an example storing an array of structures in an area of shared memory (using the shxxx functions, not mapped memory) I would be very appreciative!

Thanks,
Bob.

 

[brudnakm]

Think about how you would do it with malloc()...


typedef _myStruct {
float number ;
int anotherNumber ;
char aString[ 80 ] ;
FILE *openFile ;
etc... ;
} myStruct ;

...

int N = 44 ; /* ?????? */
myStruct *self ; /* pointer to your array of any size */

self = (myStruct*)malloc (sizeof(myStruct) * N) ;

... well shmat works the same way..

int id ;

id = shmget( key, sizeof(myStruct) * N, mode ) ;
self = (myStruct*)shmat( id ) ;

... in either case you reference the elements of the array as follows ...

for (i=0 ; i<N ; i++) {
self[ i ].number = 3.14159 ;
self[ i ].anotherNumber = 3 ;
etc...
}


Hope this helps,

Brudnakm