Eric Blake wrote:
> By the way, is it safe to assume wchar_t exists
No it isn't. Good point. Either the module description should have
#if HAVE_WCHAR_T
# include "wcwidth.h"
#endif
or wcwidth.h should protect against this case itself. The latter is
obviously better.
> Also, on mingw, where sizeof(wchar_t)==2 but
> sizeof(int)==4, a prototype of
> int wcwidth()
> is incompatible with a declaration of
> int wcwidth(wchar_t wc)
> because of promotion rules.
Yes, but that's not a reason for removing the declaration and not
testing HAVE_DECL_WCWIDTH any more.
If wchar_t is really only 16 bit, and if we write
extern int wcwidth(wchar_t wc);
some compilers on some platforms might not zero/sign-extend the argument
when passing a 16-bit value. (I.e. they might pass garbage in the upper
16 bits of the argument word.) Whereas when we write
extern int wcwidth(int wc);
we tell the compiler to do a zero/sign-extend. This is safer.
Further issues:
- In mbswidth.c you removed the includes of <wchar.h> and <wctype.h>.
But they are needed for iswcntrl(). Things are more maintainable if
you write down the includes, even if they are *currently* redundant,
because when someone will change wcwidth.h in the future, he will
certainly not look at recompiling mbswidth.c.
- When 'inline' is used, we must arrange to invoke AC_C_INLINE.
I fixed these, patch appended.
Bruno
diff -c -3 -r1.1 wcwidth.h
*** lib/wcwidth.h 28 Jun 2006 13:11:03 -0000 1.1
--- lib/wcwidth.h 28 Jun 2006 16:52:51 -0000
***************
*** 18,43 ****
#ifndef _gl_WCWIDTH_H
#define _gl_WCWIDTH_H
/* Get wcwidth if available, along with wchar_t. */
! #if HAVE_WCHAR_H
/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
<wchar.h>.
BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
<wchar.h>. */
! # include <stdio.h>
! # include <time.h>
! # include <wchar.h>
! #endif
/* Get iswprint. */
! #if HAVE_WCTYPE_H
! # include <wctype.h>
! #endif
! #if !defined iswprint && !HAVE_ISWPRINT
! # define iswprint(wc) 1
! #endif
! #if !defined wcwidth && !HAVE_WCWIDTH
/* wcwidth doesn't exist, so assume all printable characters have
width 1. */
--- 18,49 ----
#ifndef _gl_WCWIDTH_H
#define _gl_WCWIDTH_H
+ #if HAVE_WCHAR_T
+
/* Get wcwidth if available, along with wchar_t. */
! # if HAVE_WCHAR_H
/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
<wchar.h>.
BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
<wchar.h>. */
! # include <stdio.h>
! # include <time.h>
! # include <wchar.h>
! # endif
/* Get iswprint. */
! # if HAVE_WCTYPE_H
! # include <wctype.h>
! # endif
! # if !defined iswprint && !HAVE_ISWPRINT
! # define iswprint(wc) 1
! # endif
! # ifndef HAVE_DECL_WCWIDTH
! "this configure-time declaration test was not run"
! # endif
! # ifndef wcwidth
! # if !HAVE_WCWIDTH
/* wcwidth doesn't exist, so assume all printable characters have
width 1. */
***************
*** 47,52 ****
return wc == 0 ? 0 : iswprint (wc) ? 1 : -1;
}
! #endif
#endif /* _gl_WCWIDTH_H */
--- 53,70 ----
return wc == 0 ? 0 : iswprint (wc) ? 1 : -1;
}
! # elif !HAVE_DECL_WCWIDTH
!
! /* wcwidth exists but is not declared. */
! extern
! # ifdef __cplusplus
! "C"
! # endif
! int wcwidth (int /* actually wchar_t */);
!
! # endif
! # endif
!
! #endif /* HAVE_WCHAR_H */
#endif /* _gl_WCWIDTH_H */
diff -c -3 -r1.15 mbswidth.c
*** lib/mbswidth.c 28 Jun 2006 13:11:03 -0000 1.15
--- lib/mbswidth.c 28 Jun 2006 16:52:51 -0000
***************
*** 32,41 ****
/* Get isprint(). */
#include <ctype.h>
! /* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth(). */
#include "wcwidth.h"
/* Get iswcntrl(). */
#if !defined iswcntrl && !HAVE_ISWCNTRL
# define iswcntrl(wc) 0
#endif
--- 32,55 ----
/* Get isprint(). */
#include <ctype.h>
! /* Get mbstate_t, mbrtowc(), mbsinit(). */
! #if HAVE_WCHAR_H
! /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
! <wchar.h>.
! BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
! <wchar.h>. */
! # include <stdio.h>
! # include <time.h>
! # include <wchar.h>
! #endif
!
! /* Get wcwidth(). */
#include "wcwidth.h"
/* Get iswcntrl(). */
+ #if HAVE_WCTYPE_H
+ # include <wctype.h>
+ #endif
#if !defined iswcntrl && !HAVE_ISWCNTRL
# define iswcntrl(wc) 0
#endif
diff -c -3 -r1.1 wcwidth.m4
*** m4/wcwidth.m4 28 Jun 2006 13:10:13 -0000 1.1
--- m4/wcwidth.m4 28 Jun 2006 16:52:52 -0000
***************
*** 1,17 ****
! # wcwidth.m4 serial 1
dnl Copyright (C) 2006 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
- dnl autoconf tests required for use of mbswidth.c
-
AC_DEFUN([gl_FUNC_WCWIDTH],
! [ AC_CHECK_HEADERS_ONCE([wchar.h wctype.h])
! AC_CHECK_FUNCS_ONCE([iswprint wcwidth])
!
AC_REQUIRE([AC_GNU_SOURCE])
AC_CACHE_CHECK([whether wcwidth is declared], [ac_cv_have_decl_wcwidth],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
/* AIX 3.2.5 declares wcwidth in <string.h>. */
--- 1,20 ----
! # wcwidth.m4 serial 2
dnl Copyright (C) 2006 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_WCWIDTH],
! [
! dnl Persuade glibc <wchar.h> to declare wcwidth().
AC_REQUIRE([AC_GNU_SOURCE])
+ AC_REQUIRE([AC_C_INLINE])
+ AC_REQUIRE([gt_TYPE_WCHAR_T])
+
+ AC_CHECK_HEADERS_ONCE([wchar.h wctype.h])
+ AC_CHECK_FUNCS_ONCE([iswprint wcwidth])
+
AC_CACHE_CHECK([whether wcwidth is declared], [ac_cv_have_decl_wcwidth],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
/* AIX 3.2.5 declares wcwidth in <string.h>. */
diff -c -3 -r1.1 wcwidth
*** modules/wcwidth 28 Jun 2006 13:11:32 -0000 1.1
--- modules/wcwidth 28 Jun 2006 16:52:52 -0000
***************
*** 4,9 ****
--- 4,10 ----
Files:
lib/wcwidth.h
m4/wcwidth.m4
+ m4/wchar_t.m4
Depends-on:
