Shared Memory

[sajiv77]

Hi
I want to populate a number in the Shared Memory of Linux.
Iam doing the following
This is my header file which contains the Shared memory structures

#ifndef _DATABASE_SHARED_
#define _DATABASE_SHARED_

typedef struct
{
char m_sTransactionNo[15];

} DBShared;
#define _SHM_KEY (key_t)0x100
#define _SHM_SZ sizeof(_SHM)

#endif
----------------------------------------------------
This function gets the shared memory

DBShared * GetDBSharedMemory()
{
static DBShared * pSharedMemory = NULL;

if (!pSharedMemory)
{
int nShmID = shmget( _SHM_KEY, _SHM_SZ, 0);
if ( nShmID >= 0)
{
pSharedMemory = (DBShared*) shmat( nShmID, 0L, 0);
}
}
return pSharedMemory;
}

Now how do i populate the stucture's element m_sTransactionNo with a number which is 14 character long ex A7247274724727"

Also,how do i read the same .
Can anybody help me in writing a good c++ program for it

Thanks in advance

 

[OttSens]

I'm a believer in the "Keep it simple stupid" school.

char* pSharedMemory;
int nShmID;
if((nShmID = shmget( _SHM_KEY,0, 0))<0)
exit(EXIT_FAILURE);

if((pSharedMemory = shmat( nShmID, 0L, 0))<(char*)0)
exit(EXIT_FAILURE);

pSharedMemory=malloc(sizeof(char)*BUFFER_SIZE)
for(int i=0;i<BUFFER_SIZE;i++)
pSharedMemory=data;