uchar-h: <string.h> etc. namespace cleanup

This is only a partial cleanup; to be cleaner we’d need to move declarations of Gnulib extensions like c32isalpha into a separate .h file. However, if no Gnulib modules that extend <uchar.h> are used, Gnulib <uchar.h> is now pretty clean on recent GNUish platforms. * lib/uchar.in.h: On GNUish platforms, include <stdint.h>, <wchar.h>, <wctype.h> only if needed. Do not include <string.h>, as we never need it directly: even if we use <string.h>’s memset via mbszero, <wchar.h> should include <string.h> if needed, as <wchar.h> defines mbszero. Move a static_assert from here to tests, as the static_assert uses a symbol that is no longer guaranteed to be visible. * modules/uchar-h (Depends-on): Do not depend on assert-h. * tests/test-uchar-h.c: Move a static_assert here from lib/uchar.in.h, and include <wchar.h> so that wchar_t is guaranteed to be visible.
2026-04-28 06:33:36 +00:00 · 2026-04-24 16:00:34 -07:00
parent cfe5d0405f
commit b6d5b2f729
5 changed files with 102 additions and 25 deletions
--- a/19
+++ b/19
@@ -1,3 +1,22 @@
+2026-04-24  Paul Eggert  <eggert@cs.ucla.edu>
+
+	uchar-h: <string.h> etc. namespace cleanup
+	This is only a partial cleanup; to be cleaner we’d need to
+	move declarations of Gnulib extensions like c32isalpha
+	into a separate .h file.  However, if no Gnulib modules that
+	extend <uchar.h> are used, Gnulib <uchar.h> is now pretty clean on
+	recent GNUish platforms.
+	* lib/uchar.in.h: On GNUish platforms, include <stdint.h>,
+	<wchar.h>, <wctype.h> only if needed.  Do not include <string.h>,
+	as we never need it directly: even if we use <string.h>’s memset
+	via mbszero, <wchar.h> should include <string.h> if needed, as
+	<wchar.h> defines mbszero.  Move a static_assert from here to tests,
+	as the static_assert uses a symbol that is no longer guaranteed
+	to be visible.
+	* modules/uchar-h (Depends-on): Do not depend on assert-h.
+	* tests/test-uchar-h.c: Move a static_assert here from lib/uchar.in.h,
+	and include <wchar.h> so that wchar_t is guaranteed to be visible.
+
 2026-04-24  Bruno Haible  <bruno@clisp.org>

 	version-etc: Optionally emit another line for the man page.
--- a/doc/posix-headers/uchar.texi
+++ b/doc/posix-headers/uchar.texi
@@ -5,7 +5,8 @@ ISO C23 specification:@* @url{https://www.open-std.org/jtc1/sc22/wg14/www/docs/n

 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/uchar.h.html}

-Defines the types @code{char16_t}, @code{char32_t} and declares the
+Defines the types @code{char16_t}, @code{char32_t},
+@code{mbstate_t} and @code{size_t}, and declares the
 functions @code{mbrtoc16}, @code{c16rtomb}, @code{mbrtoc32},
@code{c32rtomb}.

@@ -35,6 +36,28 @@ This is the case in ISO C 11 compliant but not ISO C 23 compliant
 implementations.
@end itemize

+Portability problems fixed by Gnulib modules
+@code{btoc32},
+@code{c32_apply_mapping}, @code{c32_apply_type_test},
+@code{c32_get_mapping}, @code{c32_get_type_test},
+@code{c32isalnum}, @code{c32isalpha}, @code{c32isblank},
+@code{c32iscntrl}, @code{c32isdigit}, @code{c32isgraph},
+@code{c32islower}, @code{c32isprint}, @code{c32ispunct},
+@code{c32isspace}, @code{c32isupper}, @code{c32isxdigit},
+@code{c32rtomb}, @code{c32snrtombs}, @code{c32srtombs},
+@code{c32stombs}, @code{c32swidth}, @code{c32tob},
+@code{c32tolower}, @code{c32toupper}, @code{c32width}:
+@itemize
+@item
+The @code{char32_t} type of ISO C 23 and POSIX @code{<uchar.h>} lacks
+counterparts of several standard @code{wchar_t} functions declared in
+@code{<wchar.h>} and @code{<wctype.h>}.
+This shortcoming is ameliorated by these Gnulib modules,
+each of which arranges for @code{<uchar.h>} to declare a
+Gnulib-specific function and to make visible the symbols @code{wint_t}
+and @code{WEOF} if the symbols are part of that function's API.
+@end itemize
+
 Portability problems not fixed by Gnulib:
@itemize
@item
--- a/lib/uchar.in.h
+++ b/lib/uchar.in.h
@@ -53,15 +53,48 @@
 #error "Please include config.h first."
 #endif

-/* Get uint_least16_t, uint_least32_t.  */
-#include <stdint.h>
+/* If needed, get uint_least16_t, uint_least32_t.
+   Although POSIX allows <uchar.h> to make all symbols visible from <stdint.h>,
+   our includers should not rely on this.  */
+#if (! (defined __cplusplus \
+        ? @CXX_HAVE_UCHAR_H@ || @CXX_HAS_UCHAR_TYPES@ \
+        : @HAVE_UCHAR_H@) \
+     || @GNULIBHEADERS_OVERRIDE_CHAR16_T@ || @GNULIBHEADERS_OVERRIDE_CHAR32_T@)
+# include <stdint.h>
+#endif

-/* Get mbstate_t, size_t.  */
-#include <wchar.h>
+/* If needed, get btowc, mbstate_t, mbszero, size_t, wctob, wint_t, WEOF.
+   Although POSIX allows <uchar.h> to make all symbols visible from <wchar.h>,
+   our includers should not rely on this, except they can rely on wint_t and WEOF
+   when part of the API of a Gnulib module extending <uchar.h> that needs
+   these two symbols.  */
+#if (! (/* The underlying <uchar.h> defines mbstate_t, size_t.  */ \
+        defined __cplusplus ? @CXX_HAVE_UCHAR_H@ : @HAVE_UCHAR_H@) \
+     || (/* These need wint_t and maybe WEOF and a <wchar.h> function.  */ \
+         @GNULIB_BTOC32@ || @GNULIB_C32TOB@) \
+     || (/* These need mbszero.  */ \
+         (@GNULIB_C32STOMBS@ || @GNULIB_MBSTOC32S@)))
+# include <wchar.h>
+#endif

-/* For the inline functions.  */
-#include <string.h>
-#include <wctype.h>
+/* If needed, get iswalnum, iswalpha, iswblank, iswcntrl, iswctype,
+   iswdigit, iswgraph, iswlower, iswprint, iswpunct, iswspace,
+   iswupper, iswxdigit, towctrans, towlower, towupper, wctrans,
+   wctrans_t, wctype, wctype_t, wint_t, WEOF.
+   Our includers should not rely on this, except they can rely on wint_t and WEOF
+   when part of the API of a Gnulib module extending <uchar.h> that needs
+   these two symbols.  */
+#if (/* These need wint_t and maybe wctrans_t, wctype_t, WEOF, \
+        and a <wchar.h> function.  */ 0 \
+     || @GNULIB_C32ISALNUM@ || @GNULIB_C32ISALPHA@ || @GNULIB_C32ISBLANK@ \
+     || @GNULIB_C32ISCNTRL@ || @GNULIB_C32ISDIGIT@ || @GNULIB_C32ISGRAPH@ \
+     || @GNULIB_C32ISLOWER@ || @GNULIB_C32ISPRINT@ || @GNULIB_C32ISPUNCT@ \
+     || @GNULIB_C32ISSPACE@ || @GNULIB_C32ISUPPER@ || @GNULIB_C32ISXDIGIT@ \
+     || @GNULIB_C32TOLOWER@ || @GNULIB_C32TOUPPER@ \
+     || @GNULIB_C32_APPLY_MAPPING@ || @GNULIB_C32_APPLY_TYPE_TEST@ \
+     || @GNULIB_C32_GET_MAPPING@ || @GNULIB_C32_GET_TYPE_TEST@)
+# include <wctype.h>
+#endif

 /* The __attribute__ feature is available in gcc versions 2.5 and later.
   The attribute __pure__ was added in gcc 2.96.  */
@@ -86,8 +119,7 @@ _GL_INLINE_HEADER_BEGIN
 #if !(defined __cplusplus ? @CXX_HAVE_UCHAR_H@ || @CXX_HAS_CHAR8_TYPE@ : @HAVE_UCHAR_H@)

 /* An 8-bit variant of wchar_t.
-   Note: This type is only mandated by ISO C 23 or newer, and it does
-   denote UTF-8 units.  */
+   Note: This type is mandated by ISO C 23 or newer, and denotes UTF-8 units.  */
 typedef unsigned char char8_t;

 #elif @GNULIBHEADERS_OVERRIDE_CHAR8_T@
@@ -100,9 +132,9 @@ typedef unsigned char gl_char8_t;
 #if !(defined __cplusplus ? @CXX_HAVE_UCHAR_H@ || @CXX_HAS_UCHAR_TYPES@ : @HAVE_UCHAR_H@)

 /* A 16-bit variant of wchar_t.
-   Note: This type is only mandated by ISO C 11 or newer.  In ISO C 23
+   Note: This type is mandated by ISO C 11 or newer.  In ISO C 23
   and newer, it denotes UTF-16 units; in older versions of ISO C it did
-   so only on platforms on which __STDC_UTF_16__ was defined.  */
+   so on platforms on which __STDC_UTF_16__ was defined.  */
 typedef uint_least16_t char16_t;

 #elif @GNULIBHEADERS_OVERRIDE_CHAR16_T@
@@ -115,9 +147,9 @@ typedef uint_least16_t gl_char16_t;
 #if !(defined __cplusplus ? @CXX_HAVE_UCHAR_H@ || @CXX_HAS_UCHAR_TYPES@ : @HAVE_UCHAR_H@)

 /* A 32-bit variant of wchar_t.
-   Note: This type is only mandated by ISO C 11 or newer.  In ISO C 23
+   Note: This type is mandated by ISO C 11 or newer.  In ISO C 23
   and newer, it denotes UTF-32 code points; in older versions of ISO C
-   it did so only on platforms on which __STDC_UTF_32__ was defined.
+   it did so on platforms on which __STDC_UTF_32__ was defined.
   In gnulib, we guarantee that it denotes UTF-32 code points if and
   only if the module 'uchar-h-c23' is in use.  */
 typedef uint_least32_t char32_t;
@@ -145,17 +177,15 @@ typedef uint_least32_t gl_char32_t;
     - because GCC >= 4.9 defines these macros on all platforms, even on
       FreeBSD and Solaris.
   We should better not use __STD_UTF_16__, __STD_UTF_32__ either, because
-   these macros are misspellings, only defined by Android's <uchar.h>.  */
+   these macros are misspellings, defined only by Android's <uchar.h>.  */
 #if defined __STDC_ISO_10646__ && !_GL_SMALL_WCHAR_T
 /* glibc, musl libc */
 # define _GL_WCHAR_T_IS_UCS4 1
 #endif
-#if _GL_WCHAR_T_IS_UCS4
-static_assert (sizeof (char32_t) == sizeof (wchar_t));
-#endif


-/* Convert a single-byte character to a 32-bit wide character.  */
+/* Convert a single-byte character C to a 32-bit wide character,
+   or to WEOF if C is invalid.  */
 #if @GNULIB_BTOC32@
 # if _GL_WCHAR_T_IS_UCS4 && !defined IN_BTOC32
 _GL_BEGIN_C_LINKAGE
@@ -471,7 +501,7 @@ _GL_CXXALIASWARN (c32width);
 #endif


-/* Converts a 32-bit wide character to a multibyte character.  */
+/* Convert a 32-bit wide character to a multibyte character.  */
 #if @GNULIB_C32RTOMB@
 # if @REPLACE_C32RTOMB@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -599,8 +629,8 @@ _GL_CXXALIASWARN (c32swidth);
 #endif


-/* Converts a 32-bit wide character to unibyte character.
-   Returns the single-byte representation of WC if it exists,
+/* Convert a 32-bit wide character to unibyte character.
+   Return the single-byte representation of WC if it exists,
   or EOF otherwise.  */
 #if @GNULIB_C32TOB@
 # if _GL_WCHAR_T_IS_UCS4 && !defined IN_C32TOB
@@ -623,7 +653,7 @@ _GL_CXXALIASWARN (c32tob);
 #endif


-/* Converts a multibyte character to a 32-bit wide character.  */
+/* Convert a multibyte character to a 32-bit wide character.  */
 #if @GNULIB_MBRTOC32@
 # if @REPLACE_MBRTOC32@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -653,7 +683,7 @@ _GL_WARN_ON_USE (mbrtoc32, "mbrtoc32 is not portable - "
 #endif


-/* Converts a multibyte character and returns the next 16-bit wide
+/* Convert a multibyte character and returns the next 16-bit wide
   character.  */
 #if @GNULIB_MBRTOC16@
 # if @REPLACE_MBRTOC16@
--- a/modules/uchar-h
+++ b/modules/uchar-h
@@ -13,7 +13,6 @@ snippet/arg-nonnull
 snippet/c++defs
 snippet/warn-on-use
 extern-inline
-assert-h
 stdint-h
 wchar-h
 wctype-h
--- a/tests/test-uchar-h.c
+++ b/tests/test-uchar-h.c
@@ -20,6 +20,12 @@

 #include <uchar.h>

+#include <wchar.h>
+
+#if _GL_WCHAR_T_IS_UCS4
+static_assert (sizeof (char32_t) == sizeof (wchar_t));
+#endif
+
 /* Check that the types are defined.  */
 mbstate_t a = { 0 };
 size_t b = 5;