Don't set terminal flags twice in a row

I find this odd 'set flags twice' ancient code and comment annoyingly
distracting.  It may well be that the reason for the double-set was
simply a copy/paste mistake, and that we've been doing this for
decades [1] for no good reason.  Let's just get rid of it, and if we
find a real reason, add it back with a comment explaining why it's
necessary.

[1] This double-set was already in gdb 2.4 / 1988, the oldest release
we have sources for, and imported in git.  From 'git show 7b4ac7e1ed2c
inflow.c':

   +void
   +terminal_inferior ()
   +{
   +  if (terminal_is_ours)   /*  && inferior_thisrun_terminal == 0) */
   +    {
   +      fcntl (0, F_SETFL, tflags_inferior);
   +      fcntl (0, F_SETFL, tflags_inferior);

The "is there a reason" comment was added in 1993, by:

  commit a88797b5eadf31e21804bc820429028bf708fbcd
  Author:     Fred Fish <fnf@specifix.com>
  AuthorDate: Thu Aug 5 01:33:45 1993 +0000

gdb/ChangeLog:
2017-11-06  Pedro Alves  <palves@redhat.com>

	* inflow.c (child_terminal_inferior, child_terminal_ours_1): No
	longer set flags twice in row.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ba45ff42395de0d85c9d1a71d7f1783df97d159b..c569d568ff26376794d0a67e299ce9caacd205a7 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2017-11-06  Pedro Alves  <palves@redhat.com>
+
+       * inflow.c (child_terminal_inferior, child_terminal_ours_1): No
+       longer set flags twice in row.
+
 2017-11-06  Pedro Alves  <palves@redhat.com>
 
        * Makefile.in (SER_HARDWIRE): Update comment.

diff --git a/gdb/inflow.c b/gdb/inflow.c
index a96d4fc4a513ad75cd469337f206e9ba7a527c7a..d46d6938e27d4e555a672a713f4793a62096a169 100644 (file)
--- a/gdb/inflow.c
+++ b/gdb/inflow.c
@@ -244,10 +244,6 @@ child_terminal_inferior (struct target_ops *self)
       int result;
 
 #ifdef F_GETFL
-      /* Is there a reason this is being done twice?  It happens both
-         places we use F_SETFL, so I'm inclined to think perhaps there
-         is some reason, however perverse.  Perhaps not though...  */
-      result = fcntl (0, F_SETFL, tinfo->tflags);
       result = fcntl (0, F_SETFL, tinfo->tflags);
       OOPSY ("fcntl F_SETFL");
 #endif
@@ -403,11 +399,6 @@ child_terminal_ours_1 (int output_only)
 
 #ifdef F_GETFL
       tinfo->tflags = fcntl (0, F_GETFL, 0);
-
-      /* Is there a reason this is being done twice?  It happens both
-         places we use F_SETFL, so I'm inclined to think perhaps there
-         is some reason, however perverse.  Perhaps not though...  */
-      result = fcntl (0, F_SETFL, our_terminal_info.tflags);
       result = fcntl (0, F_SETFL, our_terminal_info.tflags);
 #endif
     }