diff options
Diffstat (limited to 'gcc/ada/s-taskin.ads')
| -rw-r--r-- | gcc/ada/s-taskin.ads | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/gcc/ada/s-taskin.ads b/gcc/ada/s-taskin.ads index a9b1812b7dc..ae6908dac49 100644 --- a/gcc/ada/s-taskin.ads +++ b/gcc/ada/s-taskin.ads @@ -364,10 +364,12 @@ package System.Tasking is ------------------------------------ type Activation_Chain is limited private; - -- Comment required ??? + -- Linked list of to-be-activated tasks, linked through + -- Activation_Link. The order of tasks on the list is irrelevant, because + -- the priority rules will ensure that they actually start activating in + -- priority order. type Activation_Chain_Access is access all Activation_Chain; - -- Comment required ??? type Task_Procedure_Access is access procedure (Arg : System.Address); @@ -651,11 +653,14 @@ package System.Tasking is -- Normally, a task starts out with internal master nesting level one -- larger than external master nesting level. It is incremented to one by -- Enter_Master, which is called in the task body only if the compiler - -- thinks the task may have dependent tasks. It is set to for the + -- thinks the task may have dependent tasks. It is set to 1 for the -- environment task, the level 2 is reserved for server tasks of the -- run-time system (the so called "independent tasks"), and the level 3 is - -- for the library level tasks. + -- for the library level tasks. Foreign threads which are detected by + -- the run-time have a level of 0, allowing these tasks to be easily + -- distinguished if needed. + Foreign_Task_Level : constant Master_Level := 0; Environment_Task_Level : constant Master_Level := 1; Independent_Task_Level : constant Master_Level := 2; Library_Task_Level : constant Master_Level := 3; @@ -1062,14 +1067,14 @@ package System.Tasking is private Null_Task : constant Task_Id := null; - type Activation_Chain is record + type Activation_Chain is limited record T_ID : Task_Id; end record; - pragma Volatile (Activation_Chain); - -- Activation_chain is an in-out parameter of initialization procedures - -- and it must be passed by reference because the init proc may terminate + -- Activation_Chain is an in-out parameter of initialization procedures and + -- it must be passed by reference because the init proc may terminate -- abnormally after creating task components, and these must be properly - -- registered for removal (Expunge_Unactivated_Tasks). + -- registered for removal (Expunge_Unactivated_Tasks). The "limited" forces + -- Activation_Chain to be a by-reference type; see RM-6.2(4). end System.Tasking; |