Patch from Eric Norum <eric@cls.usask.ca> to implement this:

    I'd like to propose a change to RTEMS task variables that I think would
    make them more useful.  I think that it is early enough in their
    existence to still make changes to their API.

    1) Change type from `int' to `void *'.
    2) Add extra argument to task_variable_add -- if non-NULL, a pointer to
    a `destructor' function to be called when the task exits.  This function
    would be called with that task's value of the task variable as its
    argument.  In many cases, the `dtor' function could be `free'.

    rtems_status_code rtems_task_variable_add (
      rtems_id tid, void **ptr, void (*dtor)(void *));
    rtems_status_code rtems_task_variable_delete (rtems_id tid, void **ptr);

    This would be all we'd need to cleanly and efficiently support C++
    per-thread exception information without dragging in all that POSIX API
    stuff.

3 files changed, 7 insertions, 3 deletions

diff --git a/cpukit/rtems/src/tasks.c b/cpukit/rtems/src/tasks.c
index bbd9ff0dd8..5fdff2db18 100644
--- a/cpukit/rtems/src/tasks.c
+++ b/cpukit/rtems/src/tasks.c
@@ -103,6 +103,8 @@ User_extensions_routine _RTEMS_tasks_Delete_extension(
   deleted->task_variables = NULL;
   while (tvp) {
     next = tvp->next;
+    if  (tvp->dtor)
+        (*tvp->dtor)( tvp->ptr );
     _Workspace_Free( tvp );
     tvp = next;
   }
diff --git a/cpukit/rtems/src/taskvariableadd.c b/cpukit/rtems/src/taskvariableadd.c
index 4ba8b7b21b..0f1ae0895e 100644
--- a/cpukit/rtems/src/taskvariableadd.c
+++ b/cpukit/rtems/src/taskvariableadd.c
@@ -24,7 +24,8 @@
 
 rtems_status_code rtems_task_variable_add(
   rtems_id tid,
-  int *ptr
+  void **ptr,
+  void (*dtor)(void *)
 )
 {
   Thread_Control        *the_thread;
@@ -54,6 +55,7 @@ rtems_status_code rtems_task_variable_add(
     tvp = the_thread->task_variables;
     while (tvp) {
       if (tvp->ptr == ptr) {
+	tvp->dtor = dtor;
         _Thread_Enable_dispatch();
         return RTEMS_SUCCESSFUL;
       }
@@ -72,6 +74,7 @@ rtems_status_code rtems_task_variable_add(
     }
     new->var = 0;
     new->ptr = ptr;
+    new->dtor = dtor;
 
     new->next = the_thread->task_variables;
     the_thread->task_variables = new;
@@ -80,4 +83,3 @@ rtems_status_code rtems_task_variable_add(
   }
   return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
 }
-
diff --git a/cpukit/rtems/src/taskvariabledelete.c b/cpukit/rtems/src/taskvariabledelete.c
index eddaf1903d..c760f9ba39 100644
--- a/cpukit/rtems/src/taskvariabledelete.c
+++ b/cpukit/rtems/src/taskvariabledelete.c
@@ -24,7 +24,7 @@
 
 rtems_status_code rtems_task_variable_delete(
   rtems_id  tid,
-  int      *ptr
+  void    **ptr
 )
 {
   Thread_Control        *the_thread;