int open_sharedmemory(int **section, char *section_name, int section_size)
/*=============================
OPEN a mapping memory section
We suppose that the shared memory segment is already
created(allocated)
Returns Value:
0 : If failed
otherwise successfull
================================================================*/
{
key_t key;
key = (key_t) osd_getkey (section_name);
*section = NULL ;
/* Test if shared memory identified by "k" exists ? */
status = shmget( key,0,0) ;
if( status < 0 ) return 0; /* shmget failed */
/* Try to attach the shared memory to the current process */
*section = (int*)shmat(status,NULL,0) ;
if( *section == (int*)-1 ) return 0; /* shmat failed */
return status ;
}
int create_sharedmemory(int **section, char *section_name, int section_size)
/*===============================
CREATE a mapping memory section
returns 0 if failed
otherwise successfull : the shared memory id
===============================================================*/
{
key_t key;
key = (key_t) osd_getkey (section_name);
*section = NULL ;
status = shmget( key,section_size,0750 + IPC_CREAT) ;
if( status < 0 ) return 0 ; /* shmget failed */
else {
*section = (int*)shmat(status,NULL,0) ; /* shmat failed */
if( *section == (int*)-1 ) {
*section = (int*)malloc(section_size) ;
return 0 ;
}
}
return status;
}
int
open_semaphore(char *name)
/*=========================================================
OPEN a semaphore cluster
=========================================================================*/
{
int status ;
key_t key;
key = (key_t) osd_getkey (name);
status = semget(key,0,0) ;
if( status < 0 ) return (0) ; /* semget failed */
else return status;
}
int
create_semaphore(char *name)
/*=======================================================
CREATE a semaphore cluster of 32 events
=========================================================*/
{
int status ;
key_t key;
key = (key_t) osd_getkey (name);
status = semget(key,CLUSTER_NUMBER,0750 + IPC_CREAT) ;
if( status < 0 ) return (0) ; /* semget failed */
return status ;
}
