Include "__fpending.h" once again.

[gnulib.git] / lib / closeout.c

diff --git a/lib/closeout.c b/lib/closeout.c
index 16e6f9f..14aa1d3 100644 (file)
--- a/lib/closeout.c
+++ b/lib/closeout.c
@@ -24,6 +24,7 @@
 #include "closeout.h"
 
 #include <stdio.h>
+#include <stdbool.h>
 #include <errno.h>
 
 #include "gettext.h"
@@ -49,7 +50,7 @@ close_stdout_set_file_name (const char *file)
 }
 
 /* Close standard output, exiting with status 'exit_failure' on failure.
-   If a program writes *anything* to stdout, that program should `fflush'
+   If a program writes *anything* to stdout, that program should close
    stdout and make sure that it succeeds before exiting.  Otherwise,
    suppose that you go to the extreme of checking the return status
    of every function that does an explicit write to stdout.  The last
@@ -57,11 +58,9 @@ close_stdout_set_file_name (const char *file)
    the fclose(stdout) could still fail (due e.g., to a disk full error)
    when it tries to write out that buffered data.  Thus, you would be
    left with an incomplete output file and the offending program would
-   exit successfully.
-
-   FIXME: note the fflush suggested above is implicit in the fclose
-   we actually do below.  Consider doing only the fflush and/or using
-   setvbuf to inhibit buffering.
+   exit successfully.  Even calling fflush is not always sufficient,
+   since some file systems (NFS and CODA) buffer written/flushed data
+   until an actual close call.
 
    Besides, it's wasteful to check the return value from every call
    that writes to stdout -- just let the internal stream state record
@@ -74,19 +73,25 @@ close_stdout_set_file_name (const char *file)
 void
 close_stdout (void)
 {
-  int e = ferror (stdout) ? 0 : -1;
-
-  /* If the stream's error bit is clear and there is nothing to flush,
-     then return right away.  */
-  if (e && __fpending (stdout) == 0)
-    return;
-
-  if (fclose (stdout) != 0)
-    e = errno;
+  bool prev_fail = ferror (stdout);
+  bool none_pending = (0 == __fpending (stdout));
+  bool fclose_fail = fclose (stdout);
 
-  if (0 <= e)
+  if (prev_fail || fclose_fail)
     {
-      char const *write_error = _("write error");
+      int e = fclose_fail ? errno : 0;
+      char const *write_error;
+
+      /* If ferror returned zero, no data remains to be flushed, and we'd
+        otherwise fail with EBADF due to a failed fclose, then assume that
+        it's ok to ignore the fclose failure.  That can happen when a
+        program like cp is invoked like this `cp a b >&-' (i.e., with
+        stdout closed) and doesn't generate any output (hence no previous
+        error and nothing to be flushed).  */
+      if (e == EBADF && !prev_fail && none_pending)
+       return;
+
+      write_error = _("write error");
       if (file_name)
        error (exit_failure, e, "%s: %s", quotearg_colon (file_name),
               write_error);