Re: new module proposal: verror

[Eric Blake]

Bruno Haible <bruno <at> clisp.org> writes:

> 
> Eric Blake wrote:
> > a useful va_list error variant for use in m4, I propose this new module.  
> > Any objections to installing this?
> 
> It looks alright, except for the Ben's comment and this:
> 
> > +  AC_LIBSOURCES([verror.c, verror.h])
> > +  AC_LIBOBJ([verror])

Incorporated.

Unfortunately, xvasprintf is not LGPL, so the verror module cannot be LGPL for 
now (although if I can convince the glibc maintainers to provide verror, it 
would probably tie in to error.c much more nicely, and avoid the need for 
xvasprintf).

Also, I decided that on failure of xvasprintf, the best thing to do is abort, 
rather than invoke undefined behavior by passing NULL to *printf (since 
xvasprintf failure implies the programmer is passing invalid parameters to 
verror).  Committed as follows.

ChangeLog
2006-08-08  Eric Blake  <address@hidden>

        * modules/verror: New module.
        * MODULES.html.sh: Document it.

lib/ChangeLog
2006-08-08  Eric Blake  <address@hidden>

        * verror.h, verror.c: New files.


Index: MODULES.html.sh
===================================================================
RCS file: /sources/gnulib/gnulib/MODULES.html.sh,v
retrieving revision 1.133
diff -u -r1.133 MODULES.html.sh
--- MODULES.html.sh     25 Jul 2006 06:20:19 -0000      1.133
+++ MODULES.html.sh     8 Aug 2006 14:17:57 -0000
@@ -2084,6 +2084,7 @@
   func_module readutmp
   func_module sig2str
   func_module sysexits
+  func_module verror
   func_module visibility
   func_end_table
 
Index: lib/verror.c
===================================================================
RCS file: lib/verror.c
diff -N lib/verror.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/verror.c        8 Aug 2006 14:17:58 -0000
@@ -0,0 +1,71 @@
+/* va_list error handler for noninteractive utilities
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   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.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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.  */
+
+/* Written by Eric Blake.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "verror.h"
+#include "xvasprintf.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+#if ENABLE_NLS
+# include "gettext.h"
+#endif
+
+#ifndef _
+# define _(String) String
+#endif
+
+/* Print a message with `vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with `exit (STATUS)'.
+   Use the globals error_print_progname and error_message_count similarly
+   to error().  */
+void
+verror (int status, int errnum, const char *format, va_list args)
+{
+  verror_at_line (status, errnum, NULL, 0, format, args);
+}
+
+/* Print a message with `vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with `exit (STATUS)'.
+   If FNAME is not NULL, prepend the message with `FNAME:LINENO:'.
+   Use the globals error_print_progname, error_message_count, and
+   error_one_per_line similarly to error_at_line().  */
+void
+verror_at_line (int status, int errnum, const char *file,
+                unsigned int line_number, const char *format, va_list args)
+{
+  char *message = xvasprintf (format, args);
+  if (message)
+    error_at_line (status, errnum, file, line_number, "%s", message);
+  else
+    {
+      /* EOVERFLOW, EINVAL, and EILSEQ from xvasprintf are signs of
+         serious programmer errors.  */
+      error (0, errno, _("unable to display error message"));
+      abort ();
+    }
+  free (message);
+}
Index: lib/verror.h
===================================================================
RCS file: lib/verror.h
diff -N lib/verror.h
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/verror.h        8 Aug 2006 14:17:58 -0000
@@ -0,0 +1,54 @@
+/* Declaration for va_list error-reporting function
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   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.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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.  */
+
+#ifndef _VERROR_H
+#define _VERROR_H 1
+
+#include "error.h"
+#include <stdarg.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Print a message with `vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with `exit (STATUS)'.
+   Use the globals error_print_progname and error_message_count similarly
+   to error().  */
+
+extern void verror (int __status, int __errnum, const char *__format,
+                    va_list __args)
+     __attribute__ ((__format__ (__printf__, 3, 0)));
+
+/* Print a message with `vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with `exit (STATUS)'.
+   If FNAME is not NULL, prepend the message with `FNAME:LINENO:'.
+   Use the globals error_print_progname, error_message_count, and
+   error_one_per_line similarly to error_at_line().  */
+
+extern void verror_at_line (int __status, int __errnum, const char *__fname,
+                            unsigned int __lineno, const char *__format,
+                            va_list __args)
+     __attribute__ ((__format__ (__printf__, 5, 0)));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* verror.h */
Index: modules/verror
===================================================================
RCS file: modules/verror
diff -N modules/verror
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ modules/verror      8 Aug 2006 14:17:58 -0000
@@ -0,0 +1,25 @@
+Description:
+verror() and verror_at_line() functions: Error reporting with va_list.
+
+Files:
+lib/verror.h
+lib/verror.c
+
+Depends-on:
+error
+xvasprintf
+
+configure.ac:
+gl_VERROR
+
+Makefile.am:
+lib_SOURCES += verror.h verror.c
+
+Include:
+"verror.h"
+
+License:
+GPL
+
+Maintainer:
+Eric Blake