Resolution of issue #1

Author: nelsc

definitions.tex

@@ -4,6 +4,7 @@
 For the purposes of this document,
 the following terms and definitions apply.
 
+\begin{comment}
 \definition{thread of execution}{
 flow of control within a program,
 including a top-level statement or expression,
@@ -24,15 +25,23 @@
 There is typically significant overhead involved
 in creating a new OS thread.
 \end{note}
+\end{comment}
 
 \definition{thread}{
-thread of execution, or OS thread
+either the main thread of the program,
+or a thread created by the program using
+\tcode{thrd_create},
+or a worker thread
 }
 
-\begin{note}
-This word, when used without qualification, is ambiguous.
-\end{note}
+\definition{worker thread}{
+thread created by the implementation
+(as if by
+\tcode{thrd_create})
+for the purpose of executing tasks in parallel
+}
 
+\begin{comment}
 \definition{execution agent}{
 entity, such as an OS thread,
 that may execute a thread of execution
@@ -41,35 +50,38 @@
 Adapted from the C++ standard.
 }
 }
+\end{comment}
 
 \definition{task}{
-thread of execution within a program
+subsection of the flow of control
+within a program
 that can be correctly executed asynchronously
 with respect to
-independent threads of execution from}
+other, independent tasks in
 the program
+}
 
 \definition{concurrent program}{
 program that uses multiple concurrent interacting threads of execution,
 each with its own progress requirements
-}
 
 \begin{example}
 A program that has separate server and client threads
 is a concurrent program.
 \end{example}
+}
 
 \definition{parallel program}{
 program whose computation
 involves independent tasks,
 which may be distributed across multiple computational units
 to be executed simultaneously
-}
 
 \begin{note}
 If sufficient computational resources are available,
 a parallel program may execute significantly faster than
 an otherwise equivalent serial program.
 \end{note}
+}
 
 \end{definitions}

loopparameter.tex

@@ -117,8 +117,9 @@
 \pfx{set_num_threads}
 macro sets to
 \tcode{num_threads}
-the recommended number of execution agents to be used
-to execute the iterations of a parallel loop
+the recommended number of iterations
+to be executed concurrently
+in a parallel loop
 associated with the object pointed to by
 \tcode{hints}.
 
@@ -140,7 +141,7 @@
 of a parallel loop associated with the object pointed to by
 \tcode{hints}
 to be grouped together to be executed sequentially
-in a single thread of execution.
+as a single task.
 
 \sclause{The \tcode{schedule_kind} parameter}
 \ssclause*{Synopsis}

tasks.tex

@@ -2,12 +2,11 @@
 
 \pnum
 A task is permitted to execute
-in either the invoking OS thread
-or an OS thread implicitly created by the implementation
-to support task execution.
-Independent tasks executing in the same OS thread
+either in the invoking thread
+or in a worker thread implicitly created by the implementation.
+Independent tasks executing in the same thread
 are indeterminately sequenced with respect to one another.
-Independent tasks executing in different OS threads
+Independent tasks executing in different threads
 are unsequenced with respect to one another.
 
 \pnum
@@ -19,3 +18,14 @@
 with the completion of the associated task block,
 or with the next execution of a sync statement
 within the associated task block.
+
+\pnum
+It is unspecified whether a worker thread is reused
+for multiple tasks
+during the execution of a program.
+The lifetimes (creation and termination points)
+of worker threads are unspecified.
+An attempt by the program
+to terminate, detach or join with 
+a worker thread
+results in undefined behavior.