* cygwin.din (error): Export.

(error_at_line): Export.
(error_message_count): Export.
(error_one_per_line): Export.
(error_print_progname): Export.
* errno.cc (error_message_count): Define.
(error_one_per_line): Define.
(error_print_progname): Define.
(_verror): New static function.
(error): New function.
(error_at_line): New function.
* posix.sgml (std-gnu): Add error, error_at_line.
* include/error.h: New header.
* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.

winsup/cygwin/ChangeLog

@@ -1,3 +1,20 @@
+2011-05-17  Yaakov Selkowitz  <yselkowitz@users.sourceforge.net>
+
+	* cygwin.din (error): Export.
+	(error_at_line): Export.
+	(error_message_count): Export.
+	(error_one_per_line): Export.
+	(error_print_progname): Export.
+	* errno.cc (error_message_count): Define.
+	(error_one_per_line): Define.
+	(error_print_progname): Define.
+	(_verror): New static function.
+	(error): New function.
+	(error_at_line): New function.
+	* posix.sgml (std-gnu): Add error, error_at_line.
+	* include/error.h: New header.
+	* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.
+
 2011-05-17  Yaakov Selkowitz  <yselkowitz@users.sourceforge.net>
 
 	* cygwin.din (clock_getcpuclockid): Export.

winsup/cygwin/cygwin.din

@@ -10,6 +10,9 @@ __ctype_ptr__ DATA
 __cygwin_environ DATA
 __cygwin_user_data DATA
 _daylight DATA
+error_message_count DATA
+error_one_per_line DATA
+error_print_progname DATA
 h_errno DATA
 _impure_ptr DATA
 in6addr_any DATA
@@ -389,6 +392,8 @@ erff NOSIGFE
 _erff = erff NOSIGFE
 err SIGFE
 __errno NOSIGFE
+error SIGFE
+error_at_line SIGFE
 errx SIGFE
 euidaccess SIGFE
 execl SIGFE

winsup/cygwin/errno.cc

@@ -13,6 +13,13 @@ details. */
 #define sys_nerr FOOsys_nerr
 #define _sys_errlist FOO_sys_errlist
 #define strerror_r FOO_strerror_r
+#define __INSIDE_CYGWIN__
+#include <errno.h>
+#include <error.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include "winsup.h"
 #include "cygtls.h"
 #include "ntdll.h"
@@ -417,3 +424,67 @@ __xpg_strerror_r (int errnum, char *buf, size_t n)
   strcpy (buf, error);
   return result;
 }
+
+unsigned int error_message_count = 0;
+int error_one_per_line = 0;
+void (*error_print_progname) (void) = NULL;
+
+static void
+_verror (int status, int errnum, const char *filename, unsigned int lineno, const char *fmt, va_list ap)
+{
+  error_message_count++;
+
+  fflush (stdout);
+
+  if (error_print_progname)
+    (*error_print_progname) ();
+  else
+    fprintf (stderr, "%s:%s", program_invocation_name, filename ? "" : " ");
+
+  if (filename)
+    fprintf (stderr, "%s:%d: ", filename, lineno);
+
+  vfprintf (stderr, fmt, ap);
+
+  if (errnum != 0)
+    fprintf (stderr, ": %s", strerror (errnum));
+
+  fprintf (stderr, "\n");
+
+  if (status != 0)
+    exit (status);
+}
+
+extern "C" void
+error (int status, int errnum, const char *fmt, ...)
+{
+  va_list ap;
+  va_start (ap, fmt);
+  _verror (status, errnum, NULL, 0, fmt, ap);
+  va_end (ap);
+}
+
+extern "C" void
+error_at_line (int status, int errnum, const char *filename, unsigned int lineno, const char *fmt, ...)
+{
+  va_list ap;
+
+  if (error_one_per_line != 0)
+    {
+      static const char *last_filename;
+      static unsigned int last_lineno;
+
+      /* strcmp(3) will SEGV if filename or last_filename are NULL */
+      if (lineno == last_lineno
+          && ((!filename && !last_filename)
+              || (filename && last_filename && strcmp (filename, last_filename) == 0)))
+        return;
+
+      last_filename = filename;
+      last_lineno = lineno;
+    }
+
+  va_start (ap, fmt);
+  _verror (status, errnum, filename, lineno, fmt, ap);
+  va_end (ap);
+}

winsup/cygwin/include/cygwin/version.h

@@ -414,12 +414,14 @@ details. */
 	   pthread_attr_setstack, pthread_attr_setstackaddr.
       246: Add CLOCK_PROCESS_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID.
 	   Export clock_getcpuclockid, pthread_getcpuclockid.
+      247: Export error, error_at_line, error_message_count, error_one_per_line,
+	   error_print_progname.
      */
 
      /* Note that we forgot to bump the api for ualarm, strtoll, strtoull */
 
 #define CYGWIN_VERSION_API_MAJOR 0
-#define CYGWIN_VERSION_API_MINOR 246
+#define CYGWIN_VERSION_API_MINOR 247
 
      /* There is also a compatibity version number associated with the
 	shared memory regions.  It is incremented when incompatible

winsup/cygwin/include/error.h

@@ -0,0 +1,30 @@
+/* error.h: GNU error reporting functions
+
+   Copyright 2011 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#ifndef _ERROR_H
+#define _ERROR_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+void error (int, int, const char *, ...);
+void error_at_line (int, int, const char *, unsigned int, const char *, ...);
+
+extern unsigned int error_message_count;
+extern int error_one_per_line;
+extern void (*error_print_progname) (void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _ERROR_H */

winsup/cygwin/posix.sgml

@@ -1089,6 +1089,8 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     envz_merge
     envz_remove
     envz_strip
+    error
+    error_at_line
     euidaccess
     execvpe
     exp10