init_priority (priority)

init_priority (priority)
In Standard C++, objects defined at namespace scope are guaranteed to be initialized in an order in strict accordance with that of their definitions in a given translation unit. No guarantee is made for initializations across translation units. However, GNU C++ allows users to control the order of initialization of objects defined at namespace scope with the init_priority attribute by specifying a relative priority, a constant integral expression currently bounded between 101 and 65535 inclusive. Lower numbers indicate a higher priority.
In the following example, A would normally be created before B, but the init_priority attribute reverses that order:


          Some_Class  A  __attribute__ ((init_priority (2000)));
          Some_Class  B  __attribute__ ((init_priority (543)));
Note that the particular values of priority do not matter; only their relative ordering.