vasnprintf on mingw

[Bruno Haible]

On mingw, I got these test failures:

> test-snprintf-posix.h:2979: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-snprintf-posix.exe
> 
> test-sprintf-posix.h:2965: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-sprintf-posix.exe
> 
> test-vasnprintf-posix.c:3486: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-vasnprintf-posix.exe
> 
> test-vasprintf-posix.c:3467: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-vasprintf-posix.exe
> 
> test-snprintf-posix.h:2979: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-vsnprintf-posix.exe
> 
> test-sprintf-posix.h:2965: assertion failed
> 
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
> FAIL: test-vsprintf-posix.exe

The reason is that the m4/printf.m4 tests determines the bugs of the function
snprintf in libmingwex.a, but vasnprintf.c then called _snprintf in msvcrt.dll,
which has more bugs.

Should m4/printf.m4 use _snprintf, not snprintf?
Or should vasnprintf.c use snprintf, not _snprintf?

I'm going for the second option, for two reasons:
  - gnulib users expect to see a replacement that shrinks over time, as mingw
    gets improved and fewer bugs remain in mingw's *printf functions.
  - libintl users under mingw expect not to see bugs that are present in
    msvcrt's *printf but fixed in mingw's *printf.

It has the consequence that libintl-8.dll will contain more stuff from
libmingwex.a.


2010-04-10  Bruno Haible  <address@hidden>

        vasnprintf: Fix multiple test failures on mingw.
        * lib/vasnprintf.c (SNPRINTF) [mingw]: Define to snprintf, not
        _snprintf, or snwprintf, not _snwprintf.

--- lib/vasnprintf.c.orig       Sat Apr 10 21:29:23 2010
+++ lib/vasnprintf.c    Sat Apr 10 21:28:39 2010
@@ -148,8 +148,14 @@
 # define USE_SNPRINTF 1
 # if HAVE_DECL__SNWPRINTF
    /* On Windows, the function swprintf() has a different signature than
-      on Unix; we use the _snwprintf() function instead.  */
-#  define SNPRINTF _snwprintf
+      on Unix; we use the function _snwprintf() or - on mingw - snwprintf()
+      instead.  The mingw function snwprintf() has fewer bugs than the
+      MSVCRT function _snwprintf(), so prefer that.  */
+#  if defined __MINGW32__
+#   define SNPRINTF snwprintf
+#  else
+#   define SNPRINTF _snwprintf
+#  endif
 # else
    /* Unix.  */
 #  define SNPRINTF swprintf
@@ -167,8 +173,15 @@
 #  define USE_SNPRINTF 0
 # endif
 # if HAVE_DECL__SNPRINTF
-   /* Windows.  */
-#  define SNPRINTF _snprintf
+   /* Windows.  The mingw function snprintf() has fewer bugs than the MSVCRT
+      function _snprintf(), so prefer that.  */
+#  if defined __MINGW32__
+#   define SNPRINTF snprintf
+    /* Here we need to call the native snprintf, not rpl_snprintf.  */
+#   undef snprintf
+#  else
+#   define SNPRINTF _snprintf
+#  endif
 # else
    /* Unix.  */
 #  define SNPRINTF snprintf