macro

void printErrorMsg(char *format, ...)
{
  va_list args;
  va_start(args, format);
  printf("ERROR: ");
  vprintf(format, args);
  va_end(args);
}

PFN_vkDestroyInstance pfn_vkDestroyInstance = NULL;

#define GET_INSTANCE_LEVEL_FUN_ADDR(name) \
pfn_##name=(PFN_##name)pfn_vkGetInstanceProcAddr(g_Instance,#name); \
if(pfn_##name == NULL) \
{ \
    printErrorMsg("cannot get" #name "address\n"); \
    return false; \
}

/*
without macro

pfn_vkDestroyInstance = (PFN_vkDestroyInstance)pfn_vkGetInstanceProcAddr(g_Instance,"vkDestroyInstance");

if(pfn_vkDestroyInstance==NULL)
{
    printErrorMsg("cannot get vkDestroyInstance address\n");
    return false;
}
*/

GET_INSTANCE_LEVEL_FUN_ADDR(vkDestroyInstance);