pshm

class pshm : public pipc

pshm is a simple encapsulation of the system V shared memory IPC

Inheritance:

Public Methods
static int exists(int size, key_t my_key, char *filename = NULL ): returns true if it exists
void* get_addr(): returns the address of the shared memory
pshm(int size, key_t key = IPC_PRIVATE, char *filename = NULL): creates a shm of size bytes
pshm(int *pId ): attaches to a shared memory with identifier *pId
static int remove(int id): forces the removal of the shm
int set_uid( uid_t new_uid ): sets the uid of the shm

Private Fields
void* addr: address where the memory is attached - different for different processes

Private Methods
void addToCleanupScript( int theId ): to add the shared memory into the cleanup script

Inherited from pipc:

Public Methods
int get_id()
key_t get_key()
int get_size()
int get_status()
int i_created()

Protected Methods
static key_t get_existing_key( char *filename, key_t key )
static key_t get_key( char *filename, key_t key = 1, int create = -1 )
static key_t get_new_key( char *filename, key_t key )

Protected
protected data members for access from derived class

int id
identifier
int size
size
key_t key
the unique key
int status
status of the last command
time_t time_created
time when the resource was created
int created
whether the process was the one that created the resource (or just attached to it)
static char* pcIpcCleanupFile
Pointer to the cleanup file name that has to be created if we want to have a script at the end that eliminates all IPC resources

Documentation

pshm is a simple encapsulation of the system V shared memory IPC.
USAGE:
 pshm::pshm( int size, key_t, char *file );
 pshm::pshm( int *pId ) : this constructor is used in
                          order to attach to an existing
                          shm.
                          NOTE: we use int and int* in  
                          to distinguish the two constructors
			  
MODIFICATIONS:

Add member function addToCleanupScript which builds up a cleanup script that can be executed to delete the IPC resources if one chooses to.

pshm(int size, key_t key = IPC_PRIVATE, char *filename = NULL)

creates a shm of size bytes

pshm(int *pId )