This example shows how to give access to a shared memory object to another process.

#define INCL_DOSMEMMGR   /* Include DOS Memory Management APIs */
#define INCL_DOSERRORS   /* DOS error values                   */
#include <os2.h>
#include <stdio.h>
#include <string.h>

int main (USHORT argc, PCHAR argv[])
{
   PVOID  pvShrObject = NULL;      /* Pointer to shared memory object      */
   ULONG  ulObjSize   = 0;         /* Size of memory object                */
   PID    pidSharer   = 0;         /* Process ID for partner               */
   APIRET rc          = NO_ERROR;  /* Return code                          */

   /************************************************************************/
   /* This example assumes that pidSharer can be initialized here with     */
   /* the process ID for the process to which we are giving the memory.    */
   /* Normally this would be passed to this program via inter-process      */
   /* communication (IPC) - a pipe, a queue, a semaphore, the file system. */
   /************************************************************************/

   ulObjSize = 4100;          /* Will be rounded to a page boundary - 8192 */

   rc = DosAllocSharedMem(&pvShrObject,   /* Pointer to object pointer     */
                          NULL,           /* Unnamed memory                */
                          ulObjSize,      /* Desired size of object        */
                          OBJ_GIVEABLE | PAG_COMMIT | PAG_WRITE | PAG_READ );
   if (rc != NO_ERROR) {
      printf("DosAllocSharedMem error:  return code = %u\n",rc);
      return 1;
   }

   rc = DosGiveSharedMem(pvShrObject,             /* Object pointer     */
                         pidSharer,               /* Process to give to */
                         PAG_WRITE | PAG_READ);   /* Memory attributes  */
   if (rc != NO_ERROR) {
      printf("DosGetSharedMem error: return code = %u\n", rc);
      return 1;
   }

   return NO_ERROR;
}