Update.

* misc/error.c (error): Handle wide oriented stderr stream correctly.
	* stdio-common/perror.c (perror): Implement according to standard.
	The stream orientation must not be changed if the stream was not
	oriented before the call.
	* stdio-common/Makefile (tests): Add tst-perror.
	* stdio-common/tst-perror.c: New file.
See ChangeLog.12 for earlier changes.

stdio-common/tst-perror.c

@@ -0,0 +1,154 @@
+/* Test of perror.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
+   To be used only for testing glibc.  */
+
+#include <errno.h>
+#include <error.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wchar.h>
+
+
+#define MB_EXP \
+  "null mode test 1: Invalid or incomplete multibyte or wide character\n" \
+  "multibyte string\n" \
+  "<0 mode test: Invalid argument\n"
+#define MB_EXP_LEN (sizeof (MB_EXP) - 1)
+
+#define WC_EXP \
+  "null mode test 2: Invalid or incomplete multibyte or wide character\n" \
+  "wide string\n" \
+  ">0 mode test: Invalid argument\n"
+#define WC_EXP_LEN (sizeof (WC_EXP) - 1)
+
+
+int
+main (void)
+{
+  int fd;
+  char fname[] = "/tmp/tst-perror.XXXXXX";
+  int result = 0;
+  char buf[200];
+  ssize_t n;
+
+  fd = mkstemp (fname);
+  if (fd == -1)
+    error (EXIT_FAILURE, errno, "cannot create temporary file");
+
+  /* Make sure the file gets removed.  */
+  unlink (fname);
+
+  fclose (stderr);
+
+  if (dup2 (fd, 2) == -1)
+    {
+      printf ("cannot create file descriptor 2: %m\n");
+      exit (EXIT_FAILURE);
+    }
+
+  stderr = fdopen (2, "w");
+  if (stderr == NULL)
+    {
+      printf ("fdopen failed: %m\n");
+      exit (EXIT_FAILURE);
+    }
+
+  if (fwide (stderr, 0) != 0)
+    {
+      printf ("stderr not initially in mode 0\n");
+      exit (EXIT_FAILURE);
+    }
+
+  errno = EILSEQ;
+  perror ("null mode test 1");
+
+  if (fwide (stderr, 0) != 0)
+    {
+      puts ("perror changed the mode from 0");
+      result = 1;
+    }
+
+  fputs ("multibyte string\n", stderr);
+
+  if (fwide (stderr, 0) >= 0)
+    {
+      puts ("fputs didn't set orientation to narrow");
+      result = 1;
+    }
+
+  errno = EINVAL;
+  perror ("<0 mode test");
+
+  fclose (stderr);
+
+  lseek (fd, 0, SEEK_SET);
+  n = read (fd, buf, sizeof (buf));
+  if (n != MB_EXP_LEN || memcmp (buf, MB_EXP, MB_EXP_LEN) != 0)
+    {
+      printf ("multibyte test failed.  Expected:\n%s\nGot:\n%.*s\n",
+	      MB_EXP, (int) n, buf);
+      result = 1;
+    }
+  else
+    puts ("multibyte test succeeded");
+
+  lseek (fd, 0, SEEK_SET);
+  ftruncate (fd, 0);
+
+  if (dup2 (fd, 2) == -1)
+    {
+      printf ("cannot create file descriptor 2: %m\n");
+      exit (EXIT_FAILURE);
+    }
+  stderr = fdopen (2, "w");
+  if (stderr == NULL)
+    {
+      printf ("fdopen failed: %m\n");
+      exit (EXIT_FAILURE);
+    }
+
+  if (fwide (stderr, 0) != 0)
+    {
+      printf ("stderr not initially in mode 0\n");
+      exit (EXIT_FAILURE);
+    }
+
+  errno = EILSEQ;
+  perror ("null mode test 2");
+
+  if (fwide (stderr, 0) != 0)
+    {
+      puts ("perror changed the mode from 0");
+      result = 1;
+    }
+
+  fputws (L"wide string\n", stderr);
+
+  if (fwide (stderr, 0) <= 0)
+    {
+      puts ("fputws didn't set orientation to wide");
+      result = 1;
+    }
+
+  errno = EINVAL;
+  perror (">0 mode test");
+
+  fclose (stderr);
+
+  lseek (fd, 0, SEEK_SET);
+  n = read (fd, buf, sizeof (buf));
+  if (n != WC_EXP_LEN || memcmp (buf, WC_EXP, WC_EXP_LEN) != 0)
+    {
+      printf ("wide test failed.  Expected:\n%s\nGot:\n%.*s\n",
+	      WC_EXP, (int) n, buf);
+      result = 1;
+    }
+  else
+    puts ("wide test succeeded");
+
+  close (fd);
+
+  return result;
+}