Re: gettext.h patch for portability to sunCC, pgCC, RHEL AS 4 g++

[Paul Eggert]

Bruno Haible <address@hidden> writes:

+ /* GCC supports variable-size arrays in C and C++ mode.
+    ISO C++ supports variable-size arrays, but some older PGI and Sun compilers
+    don't.  */
  #define _LIBGETTEXT_HAVE_VARIABLE_SIZE_ARRAYS \
!   (__GNUC__ >= 3 \
!    || (defined __cplusplus && !(defined __PGI || defined __SUNPRO_CC)))

Like Ben Pfaff, I don't understand the assertion that ISO
C++ supports variable-length arrays.  He checked the 1998
standard.  I just now checked the 2005-10-19 working draft
<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1905.pdf>,
and it doesn't require support for variable length arrays
either; section 8.3.4 (page 156, the last line) says an
array size must be a constant expression.

And there's another problem, independent of C++.  A portable
C program cannot use "defined" within a #define; the C
standard requires "defined" to work only when it is used
directly within #if (i.e., not as the result of a macro
expansion).

I propose the following patch; unlike my earlier patch, it
doesn't assume gnulib.

2006-10-25  Paul Eggert  <address@hidden>

        * lib/gettext.h (_LIBGETTEXT_HAVE_VARIABLE_SIZE_ARRAYS):
        Don't look at __cplusplus, since C++ does not require support
        for variable length arrays.  Instead, look at __STDC_VERSION__,
        since ISO C99 does require them.

--- lib/gettext.h       25 Oct 2006 16:14:34 -0000      1.9
+++ lib/gettext.h       25 Oct 2006 17:00:06 -0000
@@ -164,11 +164,9 @@ npgettext_aux (const char *domain,
 #include <string.h>
 
 /* GCC supports variable-size arrays in C and C++ mode.
-   ISO C++ supports variable-size arrays, but some older PGI and Sun compilers
-   don't.  */
+   Also, ISO C99 requires them.  */
 #define _LIBGETTEXT_HAVE_VARIABLE_SIZE_ARRAYS \
-  (__GNUC__ >= 3 \
-   || (defined __cplusplus && !(defined __PGI || defined __SUNPRO_CC)))
+  (__GNUC__ >= 3 || __STDC_VERSION__ >= 199901L)
 
 #if !_LIBGETTEXT_HAVE_VARIABLE_SIZE_ARRAYS
 #include <stdlib.h>