# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1702405209 -3600
# Node ID d3a47186d0d9c3721a82af4166405f8cdd9eb018
# Parent  02161499be5d1ad9bd955ba293587d7470eefb17
Simplified the example by using a blocking pipe and waiting function.

diff -r 02161499be5d -r d3a47186d0d9 tests/dstest_exec.cc
--- a/tests/dstest_exec.cc	Tue Dec 12 19:16:58 2023 +0100
+++ b/tests/dstest_exec.cc	Tue Dec 12 19:20:09 2023 +0100
@@ -44,13 +44,9 @@
   file_t *reader, *writer;
   long err;
 
-  /* Obtain the common notifier. */
-
-  notifier_t *notifier = client_notifier_task();
-
   /* Create a pipe for process output. */
 
-  err = client_pipe(&reader, &writer, O_NONBLOCK);
+  err = client_pipe(&reader, &writer, 0);
 
   if (err)
   {
@@ -58,14 +54,6 @@
     return err;
   }
 
-  err = client_subscribe(reader, NOTIFY_CONTENT_AVAILABLE | NOTIFY_PEER_CLOSED, notifier);
-
-  if (err)
-  {
-    printf("Could not subscribe to pipe notifications: %s\n", l4sys_errtostr(err));
-    return err;
-  }
-
   /* Start the process. */
 
   err = process_spawn(argc, argv, writer, &process);
@@ -82,59 +70,30 @@
 
   client_close(writer);
 
-  /* Wait for a signal from the process or input from the process. */
-
-  err = notify_subscribe(process_notifiable(process), NOTIFY_TASK_ALL, notifier);
+  /* Read until the pipe yields no more data. */
 
-  if (err)
-  {
-    printf("Could not subscribe to task notifications: %s\n", l4sys_errtostr(err));
-    return err;
-  }
-
-  notifiable_t *notifiable;
+  char buffer[TO_TRANSFER];
 
   while (1)
   {
-    err = notify_wait_many(&notifiable, notifier);
-
-    if (err)
-    {
-      printf("Could not wait for process: %s\n", l4sys_errtostr(err));
-      return err;
-    }
-
-    /* Handle any signal. */
-
-    if (notifiable == process_notifiable(process))
-      break;
+    offset_t nread = client_read(reader, buffer, TO_TRANSFER);
 
-    /* Handle any input. */
-
-    else if (notifiable == file_notifiable(reader))
-    {
-      char buffer[TO_TRANSFER];
-      offset_t nread = client_read(reader, buffer, TO_TRANSFER);
-
-      while (nread)
-      {
-        fwrite(buffer, sizeof(char), nread, stdout);
-        nread = client_read(reader, buffer, TO_TRANSFER);
-      }
-    }
+    if (nread)
+      fwrite(buffer, sizeof(char), nread, stdout);
+    else
+      break;
   }
 
-  notify_flags_t flags = process_notifications(process);
-  notify_values_t values = process_notification_values(process);
+  /* Close the pipe and obtain the process state. */
+
+  client_close(reader);
+
+  notify_flags_t flags;
+  notify_values_t values;
+
+  err = process_wait(process, &flags, &values);
 
   printf("End process (flags %" pFMTnotify_flags "x values: %ld, %ld)\n", flags, values.sig, values.val);
-  printf("End reader (flags %" pFMTnotify_flags "x)\n", file_notifications(reader));
-
-  err = process_error(process);
-
-  client_close(reader);
-  process_free(process);
-  client_notifier_close(notifier);
 
   return err;
 }