Patch a bug on writing to stdout, and add clearer error on openning data files

pkg/obiiter/batchiterator.go

@@ -19,18 +19,32 @@ import (
 var globalLocker sync.WaitGroup
 var globalLockerCounter = 0
 
+// RegisterAPipe increments the global lock counter and adds a new pipe to the global wait group.
+//
+// No parameters.
+// No return values.
 func RegisterAPipe() {
 	globalLocker.Add(1)
 	globalLockerCounter++
 	log.Debugln(globalLockerCounter, " Pipes are registered now")
 }
 
+// UnregisterPipe decrements the global lock counter and signals that a pipe has finished.
+//
+// No parameters.
+// No return values.
 func UnregisterPipe() {
 	globalLocker.Done()
 	globalLockerCounter--
 	log.Debugln(globalLockerCounter, "are still registered")
 }
 
+// WaitForLastPipe waits until all registered pipes have finished.
+//
+// THe function have to be called at the end of every main function.
+//
+// No parameters.
+// No return values.
 func WaitForLastPipe() {
 	globalLocker.Wait()
 }