Obtain a block of allocated named memory

• One UDR needs to allocate the named-memory block with mi_named_alloc() or mi_named_zalloc().

  This named-memory block must have a name that will be known to all UDRs that need to access the block. It must also have a memory duration that is sufficient for the required lifetime of the cached data. The UDR that allocates the named memory can access the data from the address that mi_named_alloc() or mi_named_zalloc() returns. However, once this UDR completes, the local copy of this address is deallocated.

• Any UDR that needs to access the data in the named-memory block can specify the name and memory duration of the memory block to mi_named_get().

  The mi_named_get() function returns the address of the named-memory block. The UDR can use this address to access the desired data within the named memory.

mi_integer *blk_ptr;
mi_integer status;
...
status = mi_named_alloc(sizeof(mi_integer), "cache_blk",
   PER_STMT_EXEC, &blk_ptr);

switch( status )
{
   case MI_ERROR:
      mi_db_error_raise(NULL, MI_EXCEPTION,
         "mi_named_alloc for cache_blk failed.");
      break;

   case MI_NAME_ALREADY_EXISTS:
      break;

   case MI_OK:
      *blk_ptr = 0;
      break;

   default:
      mi_db_error_raise(NULL, MI_EXCEPTION,
         "Invalid mi_named_alloc status for cache_blk");
}

mi_integer *blk_ptr;
mi_integer status;
...
status = mi_named_get("cache_blk", PER_STMT_EXEC, &blk_ptr);

switch( status )
{
   case MI_ERROR:
      mi_db_error_raise(NULL, MI_EXCEPTION,
         "mi_named_get for cache_blk failed.");
      break;

   case MI_NO_SUCH_NAME:
      /* maybe need to call mi_named_alloc() here */
      ...
      break;

   case MI_OK:
      if ( *blk_ptr > 0 )
         *blk_ptr++;
      break;

   default:
      mi_db_error_raise(NULL, MI_EXCEPTION,
         "Invalid mi_named_alloc status for cache_blk");
}