Allocating HPS Memory

To allocate HPS memory, the application calls sysctl() as follows:

           int mib[4];
           unsigned long ptrs[15];
           size_t ptrslen;
           int ret;
           mib[0] = CTL_OS2;
           mib[1] = PF_INET;
           mib[2] = IPPROTO_IP;
           mib[3] = OS2_MEMMAPIO;

           memset(ptr, 0, sizeof(ptrs));
           ptrslen = sizeof(ptrs);
           ret = sysctl(mib, sizeof(mib) / sizeof(mib[0]), ptrs,
                        &ptrslen, NULL, 0);

The TCP/IP stack will allocate 60K bytes of memory and return 15 pointers to 4K byte blocks. These must be passed on subsequent send calls with the MSG_MAPIO flag.

To allocate memory and attach a shared-event semaphore to each block as well, the application should initialize the ptrs array with the shared-event semaphore handles before calling sysctl():

           int mib[4];
           unsigned long ptrs[15];
           size_t ptrslen;
           int i;
           APIRET rc;
           int ret;

           mib[0] = CTL_OS2;
           mib[1] = PF_INET;
           mib[2] = IPPROTO_IP;
           mib[3] = OS2_MEMMAPIO;

           for (i = 0; i < sizeof(ptrs) / sizeof(ptrs[0]); i++) {
               rc = DosCreateEventSemaphore(NULL, &ptrs[i], DC_SEM_SHARED, FALSE);
               if (rc != NO_ERROR)
                  exit(1);
           }
           ptrslen = sizeof(ptrs);
           ret = sysctl(mib, sizeof(mib) / sizeof(mib[0]), ptrs, &ptrslen, NULL, 0);