Changes between Version 9 and Version 10 of Developer/Projects/SequencedInitialization


Ignore:
Timestamp:
May 11, 2010, 1:37:07 PM (9 years ago)
Author:
Sh
Comment:

/* Implementation Details */

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  • Developer/Projects/SequencedInitialization

    v9 v10  
    113113 
    114114 typedef void (*rtems_sysinit_function)(rtems_sysinit_state state);
     115= Error Handling =
     116
     117
     118 *  What should happen if an error occurs during initialization or termination?
     119 *  Should we do the error handling on a per function basis?
     120 *  Should we use a return status code and let the initialization sequencer decide what to do?
     121= Linker Set Construction =
     122
     123
     124What action will add an item to the linker set?
     125
     126# We have an explicit reference to an object which contains a linker set item.
     127# We add an object which contains a linker set item to our binary.
     128
     129Since RTEMS is used as a library the first action is trivial.
     130
     131To trigger the second action may be difficult.  Some objects may perform basic actions during system initialization but are not referenced by the application for example the board support package dependent startup.  How can we ensure that these objects will be part of the application?  Normal kernels like FreeBSD or Linux are a collection of objects and not a library.  The build process determines the set of kernel objects.
     132= C++ Support =
     133
     134
     135It should be possible to construct global C++ objects via the sequenced initialization mechanism.
     136
     137Example:
     138 static char blob [sizeof(T)];
     139 
     140 T &obj = *reinterpret_cast<T *>(blob);
     141 
     142 static void init_obj(rtems_sysinit_state state)
     143 {
     144         switch (state) {
     145                 case RTEMS_SYSINIT_STARTUP:
     146                         new (blob) T(1234567890);
     147                         break;
     148                 case RTEMS_SYSINIT_TERMINATE:
     149                         obj.~T();
     150                         break;
     151                 default:
     152                         break;
     153         }
     154 }
     155 
     156 RTEMS_SYSINIT(0, init_obj);
    115157= Open Projects =
    116158