Get available system memory

Useful Linux tips
//*****************************************************************
// Get available system memory
//*****************************************************************
float get_available_sysmem_mb ()
{
  size_t sysmem = (size_t)sysconf( _SC_PHYS_PAGES ) * (size_t)sysconf( _SC_PAGESIZE );
  return ((float)sysmem/1048576.0f);
}