From 94fe5c834904c1c2c1dfbe9e29cd5efbc7f5b284 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Thu, 21 Feb 2019 17:40:30 -0600
Subject: [PATCH] include/poll.h:  Remove un-named union from 'struct pollfd'. 
 It is not required by OpenGroup.org and violates the NuttX C coding standard
 because it is not C89 compatible.

---
 include/nuttx/compiler.h |  4 ++++
 include/poll.h           | 20 ++++++--------------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/include/nuttx/compiler.h b/include/nuttx/compiler.h
index 6b749e9ed1a..c40e3b5cfe7 100644
--- a/include/nuttx/compiler.h
+++ b/include/nuttx/compiler.h
@@ -269,6 +269,10 @@
 
 /* ISO C11 supports anonymous (unnamed) structures and unions, added in
  * GCC 4.6 (but might be suppressed with -std= option)
+ *
+ * CAREFUL: This can cause issues for shared data structures shared between
+ * C and C++ if the two versions do not support the same features.  Structures
+ * and unions can lose binary compatibility!
  */
 
 #  undef CONFIG_HAVE_ANONYMOUS_STRUCT
diff --git a/include/poll.h b/include/poll.h
index b8152162270..aa23550314b 100644
--- a/include/poll.h
+++ b/include/poll.h
@@ -114,24 +114,16 @@ typedef uint8_t pollevent_t;
 
 struct pollfd
 {
-  /* REVISIT:  Un-named unions are forbidden by the coding standard because
-   * they are not available in C89.
-   */
+  /* Standard field */
 
-#ifdef CONFIG_HAVE_ANONYMOUS_UNION
-  union
-  {
-    int        fd;      /* The descriptor being polled */
-    FAR void  *ptr;     /* The psock or file being polled */
-  };
-#else
   int          fd;      /* The descriptor being polled */
-  FAR void    *ptr;     /* The psock or file being polled */
-#endif
-
-  FAR sem_t   *sem;     /* Pointer to semaphore used to post output event */
   pollevent_t  events;  /* The input event flags */
   pollevent_t  revents; /* The output event flags */
+
+  /* Non-standard fields used internally by NuttX */
+
+  FAR void    *ptr;     /* The psock or file being polled */
+  FAR sem_t   *sem;     /* Pointer to semaphore used to post output event */
   FAR void    *priv;    /* For use by drivers */
 };