From: "edelsohn (David Edelsohn)" <dje.gcc@...>
Date: 2013-03-28T07:23:44+09:00
Subject: [ruby-core:53782] [ruby-trunk - Bug #8174] AIX header file conflict with rb_hook_list_struct


Issue #8174 has been updated by edelsohn (David Edelsohn).


I do not know why the documentation page that you referenced does not mention "events".  The same header also exists in AIX 6.1, and probably earlier.  It may have been removed in some update, but that does not address existing systems.

Ruby thread.c uses revents:

    if (fds.revents & POLLIN_SET)
        result |= RB_WAITFD_IN;
    if (fds.revents & POLLOUT_SET)
        result |= RB_WAITFD_OUT;
    if (fds.revents & POLLEX_SET)
        result |= RB_WAITFD_PRI;

so your patch causes the statements to refer to the wrong members.  It seems safer to #undef the offending macro instead of defining more macros.  Wrapping it in #ifdef _AIX is fine.

diff --git i/include/ruby/io.h w/include/ruby/io.h
index 07be55c..12ffc76 100644
--- i/include/ruby/io.h
+++ w/include/ruby/io.h
@@ -29,6 +29,9 @@ extern "C" {

 #include "ruby/config.h"
 #if defined(HAVE_POLL)
+#  ifdef _AIX
+#    undef events
+#  endif
 #  include <poll.h>
 #  define RB_WAITFD_IN  POLLIN
 #  define RB_WAITFD_PRI POLLPRI

----------------------------------------
Bug #8174: AIX header file conflict with rb_hook_list_struct
https://bugs.ruby-lang.org/issues/8174#change-37975

Author: edelsohn (David Edelsohn)
Status: Feedback
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby-2.0.0-p0


=begin
rb_hook_list_struct defines a member "events":

  typedef struct rb_hook_list_struct {
      struct rb_event_hook_struct *hooks;
      rb_event_flag_t events;
      int need_clean;
  } rb_hook_list_t;

AIX defines a macro "events" in sys/poll.h:

  struct  pollfd
  {
          long    fd;                     /* file descriptor or file ptr  */
          ushort  reqevents;              /* requested events             */
          ushort  rtnevents;              /* returned events              */
  };
  #define events  reqevents               /* SVR3,4 pollfd member name    */
  #define revents rtnevents               /* SVR3,4 pollfd member name    */

Ruby thread.c includes sys/poll.c via ruby/io.h.  This renames the structure member when referenced through EXEC_EVENT_HOOK, e.g.,

        if ((state = EXEC_TAG()) == 0) {
            SAVE_ROOT_JMPBUF(th, {
                if (!th->first_func) {
                    GetProcPtr(th->first_proc, proc);
                    th->errinfo = Qnil;
                    th->root_lep = rb_vm_ep_local_ep(proc->block.ep);
                    th->root_svar = Qnil;
                    EXEC_EVENT_HOOK(th, RUBY_EVENT_THREAD_BEGIN, th->self, 0, 0, Qundef);
                    th->value = rb_vm_invoke_proc(th, proc, (int)RARRAY_LEN(args), RARRAY_PTR(args), 0);
                    EXEC_EVENT_HOOK(th, RUBY_EVENT_THREAD_END, th->self, 0, 0, Qundef);
                }

This makes the compiler unhappy:

  compiling /usr/gnu/src/ruby-2.0.0-p0/thread.c
  /usr/gnu/src/ruby-2.0.0-p0/thread.c: In function 'thread_start_func_2':
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:496:6: error: 'rb_hook_list_t' has no member named 'reqevents'
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:496:6: error: 'rb_hook_list_t' has no member named 'reqevents'
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:496:6: error: 'rb_hook_list_t' has no member named 'reqevents'
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:496:6: error: 'rb_hook_list_t' has no member named 'reqevents'
  /usr/gnu/src/ruby-2.0.0-p0/thread.c: In function 'rb_threadptr_execute_interrupts':
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:1917:6: error: 'rb_hook_list_t' has no member named 'reqevents'
  /usr/gnu/src/ruby-2.0.0-p0/thread.c:1917:6: error: 'rb_hook_list_t' has no member named 'reqevents'

Because Ruby only uses fd member revents, one option is to change include/ruby/io.h

  # diff
   #include "ruby/config.h"
   #if defined(HAVE_POLL)
   #  include <poll.h>
  +#  undef events
   #  define RB_WAITFD_IN  POLLIN
   #  define RB_WAITFD_PRI POLLPRI
   #  define RB_WAITFD_OUT POLLOUT
=end



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