mbrtowc: Work around a Solaris 7 bug.

* m4/mbrtowc.m4 (gl_MBRTOWC_NULL_ARG1): New macro.
(gl_MBRTOWC_NULL_ARG2): Renamed from gl_MBRTOWC_NULL_ARG.
(gl_FUNC_MBRTOWC): Update. Define MBRTOWC_NULL_ARG2_BUG instead of
MBRTOWC_NULL_ARG_BUG. Invoke gl_MBRTOWC_NULL_ARG1 and define
MBRTOWC_NULL_ARG1_BUG.
* lib/mbrtowc.c (rpl_mbrtowc): Use MBRTOWC_NULL_ARG2_BUG instead of
MBRTOWC_NULL_ARG_BUG. Handle MBRTOWC_NULL_ARG1_BUG.
* tests/test-mbrtowc.c (main): Test support of a NULL first argument.
* doc/posix-functions/mbrtowc.texi: Mention the Solaris 7 bug.

1 files changed, 21 insertions, 1 deletions

diff --git a/tests/test-mbrtowc.c b/tests/test-mbrtowc.c
index 5477677c16..8022d025f7 100644
--- a/tests/test-mbrtowc.c
+++ b/tests/test-mbrtowc.c
@@ -1,5 +1,5 @@
 /* Test of conversion of multibyte character to wide character.
-   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+   Copyright (C) 2008-2010 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
@@ -143,6 +143,11 @@ main (int argc, char *argv[])
           ASSERT (mbsinit (&state));
           input[1] = '\0';
 
+          /* Test support of NULL first argument.  */
+          ret = mbrtowc (NULL, input + 2, 3, &state);
+          ASSERT (ret == 1);
+          ASSERT (mbsinit (&state));
+
           wc = (wchar_t) 0xBADFACE;
           ret = mbrtowc (&wc, input + 2, 3, &state);
           ASSERT (ret == 1);
@@ -192,6 +197,11 @@ main (int argc, char *argv[])
           ASSERT (mbsinit (&state));
           input[2] = '\0';
 
+          /* Test support of NULL first argument.  */
+          ret = mbrtowc (NULL, input + 3, 4, &state);
+          ASSERT (ret == 2);
+          ASSERT (mbsinit (&state));
+
           wc = (wchar_t) 0xBADFACE;
           ret = mbrtowc (&wc, input + 3, 4, &state);
           ASSERT (ret == 2);
@@ -250,6 +260,11 @@ main (int argc, char *argv[])
           ASSERT (mbsinit (&state));
           input[4] = '\0';
 
+          /* Test support of NULL first argument.  */
+          ret = mbrtowc (NULL, input + 5, 3, &state);
+          ASSERT (ret == 2);
+          ASSERT (mbsinit (&state));
+
           wc = (wchar_t) 0xBADFACE;
           ret = mbrtowc (&wc, input + 5, 3, &state);
           ASSERT (ret == 2);
@@ -293,6 +308,11 @@ main (int argc, char *argv[])
           ASSERT (mbsinit (&state));
           input[2] = '\0';
 
+          /* Test support of NULL first argument.  */
+          ret = mbrtowc (NULL, input + 3, 6, &state);
+          ASSERT (ret == 4);
+          ASSERT (mbsinit (&state));
+
           wc = (wchar_t) 0xBADFACE;
           ret = mbrtowc (&wc, input + 3, 6, &state);
           ASSERT (ret == 4);