Re: test-string-c++ test failure

[Bruno Haible]

Hi Jim,

> Here's a much easier way to reproduce the problem,
> using only gnulib.  The key is to test the string
> module with another, like memchr:
> 
>     $ ./gnulib-tool --test --with-tests string memchr
> 
> Here's the output I see:

Thanks. This is much easier. It is in fact the first thing I had tested, but
it did not fail for me, because I'm using an older glibc than you. The
difference is in these glibc <string.h> changes:
  
http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=d8387c7b7b1c9ae92f924c33ba05790c98464d19
  
http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=8585cb7454e10346bccc9fb4df3fae51b2efb9b6

This should fix it:


2010-03-11  Bruno Haible  <address@hidden>

        Fix problems with overloaded C++ definitions of memchr, strpbrk, etc.
        * build-aux/c++defs.h (_GL_CXXALIAS_SYS_CAST2): Make it work regardless
        whether the system provides one variant or multiple variants of the
        function.
        * lib/string.in.h (memchr, strpbrk): Use _GL_CXXALIAS_SYS_CAST2 for all
        C++ compilers.
        (memrchr, rawmemchr, strchrnul, strstr, strcasestr): Use
        _GL_CXXALIAS_SYS_CAST2 instead of _GL_CXXALIAS_SYS.
        Reported by Jim Meyering.

--- build-aux/c++defs.h.orig    Thu Mar 11 12:33:43 2010
+++ build-aux/c++defs.h Thu Mar 11 12:11:24 2010
@@ -176,16 +176,21 @@
    are used to silence the "cannot find a match" and "invalid conversion"
    errors that would otherwise occur.  */
 #if defined __cplusplus && defined GNULIB_NAMESPACE
+  /* The outer cast must be a reinterpret_cast.
+     The inner cast: When the function is defined as a set of overloaded
+     functions, it works as a static_cast<>, choosing the designated variant.
+     When the function is defined as a single variant, it works as a
+     reinterpret_cast<>. The parenthesized cast syntax works both ways.  */
 # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
     namespace GNULIB_NAMESPACE                                                \
     {                                                                         \
       static rettype (*func) parameters =                                     \
         reinterpret_cast<rettype(*)parameters>(                               \
-          reinterpret_cast<rettype2(*)parameters2>(::func));                  \
+          (rettype2(*)parameters2)(::func));                                  \
     }                                                                         \
     _GL_EXTERN_C int _gl_cxxalias_dummy
 #else
-# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
+# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
     _GL_EXTERN_C int _gl_cxxalias_dummy
 #endif
 
--- lib/string.in.h.orig        Thu Mar 11 12:33:43 2010
+++ lib/string.in.h     Thu Mar 11 12:33:18 2010
@@ -66,19 +66,12 @@
                                   _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (memchr, void *, (void const *__s, int __c, size_t __n));
 # else
-#  if defined __SUNPRO_CC
-  /* This compiler defines an overloaded function
+  /* On some systems, this function is defined as an overloaded function:
        extern "C" { const void * std::memchr (const void *, int, size_t); }
-       extern "C++" { inline void * std::memchr (void *, int, size_t); }
-     and diagnoses an error
-     "Error: Could not find a match for std::memchr(const void*, int, 
unsigned)"
-   */
+       extern "C++" { void * std::memchr (void *, int, size_t); }  */
 _GL_CXXALIAS_SYS_CAST2 (memchr,
                         void *, (void const *__s, int __c, size_t __n),
                         void const *, (void const *__s, int __c, size_t __n));
-#  else
-_GL_CXXALIAS_SYS (memchr, void *, (void const *__s, int __c, size_t __n));
-#  endif
 # endif
 _GL_CXXALIASWARN (memchr);
 #elif defined GNULIB_POSIXCHECK
@@ -150,7 +143,12 @@
                                    __attribute__ ((__pure__))
                                    _GL_ARG_NONNULL ((1)));
 # endif
-_GL_CXXALIAS_SYS (memrchr, void *, (void const *, int, size_t));
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" { const void * std::memrchr (const void *, int, size_t); }
+       extern "C++" { void * std::memrchr (void *, int, size_t); }  */
+_GL_CXXALIAS_SYS_CAST2 (memrchr,
+                        void *, (void const *, int, size_t),
+                        void const *, (void const *, int, size_t));
 _GL_CXXALIASWARN (memrchr);
 #elif defined GNULIB_POSIXCHECK
 # undef memrchr
@@ -169,7 +167,12 @@
                                      __attribute__ ((__pure__))
                                      _GL_ARG_NONNULL ((1)));
 # endif
-_GL_CXXALIAS_SYS (rawmemchr, void *, (void const *__s, int __c_in));
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" { const void * std::rawmemchr (const void *, int); }
+       extern "C++" { void * std::rawmemchr (void *, int); }  */
+_GL_CXXALIAS_SYS_CAST2 (rawmemchr,
+                        void *, (void const *__s, int __c_in),
+                        void const *, (void const *__s, int __c_in));
 _GL_CXXALIASWARN (rawmemchr);
 #elif defined GNULIB_POSIXCHECK
 # undef rawmemchr
@@ -242,7 +245,12 @@
                                      __attribute__ ((__pure__))
                                      _GL_ARG_NONNULL ((1)));
 # endif
-_GL_CXXALIAS_SYS (strchrnul, char *, (char const *__s, int __c_in));
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" { const char * std::strchrnul (const char *, int); }
+       extern "C++" { char * std::strchrnul (char *, int); }  */
+_GL_CXXALIAS_SYS_CAST2 (strchrnul,
+                        char *, (char const *__s, int __c_in),
+                        char const *, (char const *__s, int __c_in));
 _GL_CXXALIASWARN (strchrnul);
 #elif defined GNULIB_POSIXCHECK
 # undef strchrnul
@@ -340,19 +348,12 @@
                                    __attribute__ ((__pure__))
                                    _GL_ARG_NONNULL ((1, 2)));
 # endif
-# if defined __SUNPRO_CC
-  /* This compiler defines an overloaded function
+  /* On some systems, this function is defined as an overloaded function:
        extern "C" { const char * strpbrk (const char *, const char *); }
-       extern "C++" { inline char * strpbrk (char *, const char *); }
-     and diagnoses an error
-     "Error: Could not find a match for std::strpbrk(const char*, const char*)"
-   */
+       extern "C++" { char * strpbrk (char *, const char *); }  */
 _GL_CXXALIAS_SYS_CAST2 (strpbrk,
                         char *, (char const *__s, char const *__accept),
                         const char *, (char const *__s, char const *__accept));
-# else
-_GL_CXXALIAS_SYS (strpbrk, char *, (char const *__s, char const *__accept));
-# endif
 _GL_CXXALIASWARN (strpbrk);
 # if defined GNULIB_POSIXCHECK
 /* strpbrk() assumes the second argument is a list of single-byte characters.
@@ -441,7 +442,12 @@
                                   _GL_ARG_NONNULL ((1, 2)));
 _GL_CXXALIAS_RPL (strstr, char *, (const char *haystack, const char *needle));
 # else
-_GL_CXXALIAS_SYS (strstr, char *, (const char *haystack, const char *needle));
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" { const char * strstr (const char *, const char *); }
+       extern "C++" { char * strstr (char *, const char *); }  */
+_GL_CXXALIAS_SYS_CAST2 (strstr,
+                        char *, (const char *haystack, const char *needle),
+                        const char *, (const char *haystack, const char 
*needle));
 # endif
 _GL_CXXALIASWARN (strstr);
 #elif defined GNULIB_POSIXCHECK
@@ -476,8 +482,12 @@
                   (const char *haystack, const char *needle)
                   __attribute__ ((__pure__)) _GL_ARG_NONNULL ((1, 2)));
 #  endif
-_GL_CXXALIAS_SYS (strcasestr, char *,
-                  (const char *haystack, const char *needle));
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" { const char * strcasestr (const char *, const char *); }
+       extern "C++" { char * strcasestr (char *, const char *); }  */
+_GL_CXXALIAS_SYS_CAST2 (strcasestr,
+                        char *, (const char *haystack, const char *needle),
+                        const char *, (const char *haystack, const char 
*needle));
 # endif
 _GL_CXXALIASWARN (strcasestr);
 #elif defined GNULIB_POSIXCHECK