X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fclosein.c;h=c7fb581eaa5af0f7b3e6c0e65468b909638ef2fb;hb=298d8b4a29e66da0b046b64b822f97d1c8fef74b;hp=51534842624451e877783ea56d2974ac55a1b0cb;hpb=88a56a14d9b092c7e88c05f8a18c8e3fb8844ca1;p=gnulib.git

diff --git a/lib/closein.c b/lib/closein.c
index 515348426..c7fb581ea 100644
--- a/lib/closein.c
+++ b/lib/closein.c
@@ -2,10 +2,10 @@
 
    Copyright (C) 2007 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -13,13 +13,11 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
 #include "closein.h"
-#include "closeout.h"
 
 #include <errno.h>
 #include <stdbool.h>
@@ -30,8 +28,10 @@
 #define _(msgid) gettext (msgid)
 
 #include "close-stream.h"
+#include "closeout.h"
 #include "error.h"
 #include "exitfail.h"
+#include "freadahead.h"
 #include "quotearg.h"
 
 static const char *file_name;
@@ -79,18 +79,29 @@ void
 close_stdin (void)
 {
   bool fail = false;
-  if (fflush (stdin) != 0 || close_stream (stdin) != 0)
+
+  /* There is no need to flush stdin if we can determine quickly that stdin's
+     input buffer is empty; in this case we know that if stdin is seekable,
+     fseeko (stdin, 0, SEEK_CUR) == lseek (0, 0, SEEK_CUR).  */
+  if (freadahead (stdin) > 0)
     {
+      /* Only attempt flush if stdin is seekable, as fflush is entitled to
+	 fail on non-seekable streams.  */
+      if (fseeko (stdin, 0, SEEK_CUR) == 0 && fflush (stdin) != 0)
+	fail = true;
+    }
+  if (close_stream (stdin) != 0)
+    fail = true;
+  if (fail)
+    {
+      /* Report failure, but defer exit until after closing stdout,
+	 since the failure report should still be flushed.  */
       char const *close_error = _("error closing file");
       if (file_name)
 	error (0, errno, "%s: %s", quotearg_colon (file_name),
 	       close_error);
       else
 	error (0, errno, "%s", close_error);
-
-      /* Defer failure until after closing stdout, since the output
-	 can still usefully be flushed.  */
-      fail = true;
     }
 
   close_stdout ();