Improve documentation for malloc etc. (BZ#27719)

[thirdparty/glibc.git] / stdio-common / perror.c

diff --git a/stdio-common/perror.c b/stdio-common/perror.c
index c22be6daf2a24b476f04f8b85ec0c36d395782d7..fa0059d9f7b5533ec7f747d684d3604e95896ae3 100644 (file)
--- a/stdio-common/perror.c
+++ b/stdio-common/perror.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991-1993,1997,1998,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1991-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -12,23 +12,20 @@
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include <wchar.h>
+#include "libioP.h"
 
-/* Print a line on stderr consisting of the text in S, a colon, a space,
-   a message describing the meaning of the contents of `errno' and a newline.
-   If S is NULL or "", the colon and space are omitted.  */
-void
-perror (const char *s)
+static void
+perror_internal (FILE *fp, const char *s, int errnum)
 {
   char buf[1024];
-  int errnum = errno;
   const char *colon;
   const char *errstring;
 
@@ -39,10 +36,48 @@ perror (const char *s)
 
   errstring = __strerror_r (errnum, buf, sizeof buf);
 
-#ifdef USE_IN_LIBIO
-  if (_IO_fwide (stderr, 0) > 0)
-    (void) fwprintf (stderr, L"%s%s%s\n", s, colon, errstring);
+  (void) __fxprintf (fp, "%s%s%s\n", s, colon, errstring);
+}
+
+
+/* Print a line on stderr consisting of the text in S, a colon, a space,
+   a message describing the meaning of the contents of `errno' and a newline.
+   If S is NULL or "", the colon and space are omitted.  */
+void
+perror (const char *s)
+{
+  int errnum = errno;
+  FILE *fp;
+  int fd = -1;
+
+
+  /* The standard says that 'perror' must not change the orientation
+     of the stream.  What is supposed to happen when the stream isn't
+     oriented yet?  In this case we'll create a new stream which is
+     using the same underlying file descriptor.  */
+  if (__builtin_expect (_IO_fwide (stderr, 0) != 0, 1)
+      || (fd = __fileno (stderr)) == -1
+      || (fd = __dup (fd)) == -1
+      || (fp = fdopen (fd, "w+")) == NULL)
+    {
+      if (__glibc_unlikely (fd != -1))
+       __close (fd);
+
+      /* Use standard error as is.  */
+      perror_internal (stderr, s, errnum);
+    }
   else
-#endif
-    (void) fprintf (stderr, "%s%s%s\n", s, colon, errstring);
+    {
+      /* We don't have to do any special hacks regarding the file
+        position.  Since the stderr stream wasn't used so far we just
+        write to the descriptor.  */
+      perror_internal (fp, s, errnum);
+
+      if (_IO_ferror_unlocked (fp))
+       stderr->_flags |= _IO_ERR_SEEN;
+
+      /* Close the stream.  */
+      fclose (fp);
+    }
 }
+libc_hidden_def (perror)