update README

Author: unreal

README.md

@@ -1,2 +1,35 @@
-# task_status
-KAREL utility to check the status of a task from TPE
+# TASK_STATUS
+
+KAREL utility to check the status of a task from TPE.
+
+Because there's no other way to check if a task is running
+from TPE. This can be a problem if you're counting on a
+background task to be running or an asynchronous task to
+be not running before firing it off again.
+
+## Usage
+
+    CALL TASK_STATUS('PROGRAM_NAME', outputRegId) ;
+
+| Return Value | Meaning |
+| ------------ | ------- |
+| -2           | Run request has been accepted |
+| -1           | Abort request has been accepted |
+| 0            | Task is running |
+| 1            | Task is paused |
+| 2            | Task is aborted |
+| Other        | Refer to Error Code manual |
+
+
+## Example
+
+    LBL[1] ;
+    CALL TASK_STATUS(‘ASYNC_TASK’,1) ;
+    IF R[1:TASK STATUS]<>2,JMP LBL[501] ;
+    ! task is aborted ;
+    RUN ASYNC_TASK ;
+    END ;
+     ;
+    LBL[501] ;
+    ! task is still doing something or hung up ;
+    JMP LBL[1] ;