I wrote:
> So, for C++, the solution should be something with templates.
> If someone has spare time available for this, please go ahead.
The solution for C++ is easier than I thought.
2025-02-09 Bruno Haible <br...@clisp.org>
mbsstr, mbscasestr, mbspcasecmp: Use const-improved C++ templates.
* lib/string.in.h (mbsstr, mbspcasecmp, mbscasestr): In C++, define
through a template that supports both 'char *' and 'const char *'.
diff --git a/lib/string.in.h b/lib/string.in.h
index 6705967c59..bfe949cf84 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -1178,17 +1178,29 @@ _GL_CXXALIASWARN (mbsrchr);
_GL_EXTERN_C char * mbsstr (const char *haystack, const char *needle)
_GL_ATTRIBUTE_PURE
_GL_ARG_NONNULL ((1, 2));
+# ifndef _GL_NO_CONST_GENERICS
/* Don't silently convert a 'const char *' to a 'char *'. Programmers want
compiler warnings for 'const' related mistakes. */
-# if !(defined _GL_NO_CONST_GENERICS || defined __cplusplus)
-# if __STDC_VERSION__ >= 202311
-# define mbsstr(h,n) (typeof(h)) mbsstr ((h), (n))
-# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
- || defined __ICC || defined __TINYC__)
-# define mbsstr(h,n) \
- _Generic ((h), \
- char const *: (char const *) mbsstr ((h), (n)), \
- default : mbsstr ((h), (n)))
+# ifdef __cplusplus
+template <typename T>
+ T * mbsstr_template (T* haystack, const char *needle);
+template <>
+ inline char * mbsstr_template (char *haystack, const char *needle)
+ { return mbsstr (haystack, needle); }
+template <>
+ inline const char * mbsstr_template (const char *haystack, const char
*needle)
+ { return mbsstr (haystack, needle); }
+# define mbsstr mbsstr_template
+# else
+# if __STDC_VERSION__ >= 202311
+# define mbsstr(h,n) (typeof(h)) mbsstr ((h), (n))
+# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
+ || defined __ICC || defined __TINYC__)
+# define mbsstr(h,n) \
+ _Generic ((h), \
+ char const *: (char const *) mbsstr ((h), (n)), \
+ default : mbsstr ((h), (n)))
+# endif
# endif
# endif
#endif
@@ -1232,17 +1244,29 @@ _GL_EXTERN_C int mbsncasecmp (const char *s1, const
char *s2, size_t n)
_GL_EXTERN_C char * mbspcasecmp (const char *string, const char *prefix)
_GL_ATTRIBUTE_PURE
_GL_ARG_NONNULL ((1, 2));
+# ifndef _GL_NO_CONST_GENERICS
/* Don't silently convert a 'const char *' to a 'char *'. Programmers want
compiler warnings for 'const' related mistakes. */
-# if !(defined _GL_NO_CONST_GENERICS || defined __cplusplus)
-# if __STDC_VERSION__ >= 202311
-# define mbspcasecmp(s,p) (typeof(s)) mbspcasecmp ((s), (p))
-# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
- || defined __ICC || defined __TINYC__)
-# define mbspcasecmp(s,p) \
- _Generic ((s), \
- char const *: (char const *) mbspcasecmp ((s), (p)), \
- default : mbspcasecmp ((s), (p)))
+# ifdef __cplusplus
+template <typename T>
+ T * mbspcasecmp_template (T* string, const char *prefix);
+template <>
+ inline char * mbspcasecmp_template (char *string, const char *prefix)
+ { return mbspcasecmp (string, prefix); }
+template <>
+ inline const char * mbspcasecmp_template (const char *string, const char
*prefix)
+ { return mbspcasecmp (string, prefix); }
+# define mbspcasecmp mbspcasecmp_template
+# else
+# if __STDC_VERSION__ >= 202311
+# define mbspcasecmp(s,p) (typeof(s)) mbspcasecmp ((s), (p))
+# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
+ || defined __ICC || defined __TINYC__)
+# define mbspcasecmp(s,p) \
+ _Generic ((s), \
+ char const *: (char const *) mbspcasecmp ((s), (p)), \
+ default : mbspcasecmp ((s), (p)))
+# endif
# endif
# endif
#endif
@@ -1256,17 +1280,29 @@ _GL_EXTERN_C char * mbspcasecmp (const char *string,
const char *prefix)
_GL_EXTERN_C char * mbscasestr (const char *haystack, const char *needle)
_GL_ATTRIBUTE_PURE
_GL_ARG_NONNULL ((1, 2));
+# ifndef _GL_NO_CONST_GENERICS
/* Don't silently convert a 'const char *' to a 'char *'. Programmers want
compiler warnings for 'const' related mistakes. */
-# if !(defined _GL_NO_CONST_GENERICS || defined __cplusplus)
-# if __STDC_VERSION__ >= 202311
-# define mbscasestr(h,n) (typeof(h)) mbscasestr ((h), (n))
-# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
- || defined __ICC || defined __TINYC__)
-# define mbscasestr(h,n) \
- _Generic ((h), \
- char const *: (char const *) mbscasestr ((h), (n)), \
- default : mbscasestr ((h), (n)))
+# ifdef __cplusplus
+template <typename T>
+ T * mbscasestr_template (T* haystack, const char *needle);
+template <>
+ inline char * mbscasestr_template (char *haystack, const char *needle)
+ { return mbscasestr (haystack, needle); }
+template <>
+ inline const char * mbscasestr_template (const char *haystack, const char
*needle)
+ { return mbscasestr (haystack, needle); }
+# define mbscasestr mbscasestr_template
+# else
+# if __STDC_VERSION__ >= 202311
+# define mbscasestr(h,n) (typeof(h)) mbscasestr ((h), (n))
+# elif ((__GNUC__ + (__GNUC_MINOR__ >= 9) > 4) || (__clang_major__ >= 3) \
+ || defined __ICC || defined __TINYC__)
+# define mbscasestr(h,n) \
+ _Generic ((h), \
+ char const *: (char const *) mbscasestr ((h), (n)), \
+ default : mbscasestr ((h), (n)))
+# endif
# endif
# endif
#endif
