Re: clar unit testing framework FTBFS on uclibc systems (wchar_t unsupported)

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Thu, Oct 17, 2024 at 03:54:28PM +0200, Patrick Steinhardt wrote:
> Okay, uclibc indeed has _optional_ support for `wchar_t`. But what
> really throws me off: "include/wchar.h" from uclibc has the following
> snippet right at the top:
> 
>     #ifndef __UCLIBC_HAS_WCHAR__
>     #error Attempted to include wchar.h when uClibc built without wide char support.
>     #endif
> 
> We unconditionally include <wchar.h>, and your system does not seem to
> have support for it built in. So why doesn't the `#error` trigger? It's
> also not like this is a recent error, it has been added with 581deed72
> (The obligatory forgotten files..., 2002-05-06).
> 
> We can do something like the below patch in clar, but I'd first like to
> understand why your platform seems to be broken in such a way.
> 
> Patrick
> 
> diff --git a/clar.c b/clar.c
> index 64879cf..06fe3d1 100644
> --- a/clar.c
> +++ b/clar.c
> @@ -9,6 +9,11 @@
>  #define _DARWIN_C_SOURCE
>  #define _DEFAULT_SOURCE
>  
> +#if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_WCHAR__)
> +#else
> +#	define HAVE_WCHAR
> +#endif
> +
>  #include <errno.h>
>  #include <setjmp.h>
>  #include <stdlib.h>
> @@ -16,7 +21,9 @@
>  #include <string.h>
>  #include <math.h>
>  #include <stdarg.h>
> +#ifdef HAVE_WCHAR
>  #include <wchar.h>
> +#endif
>  #include <time.h>
>  #include <inttypes.h>
>  
> @@ -766,6 +773,7 @@ void clar__assert_equal(
>  			}
>  		}
>  	}
> +#ifdef HAVE_WCHAR
>  	else if (!strcmp("%ls", fmt)) {
>  		const wchar_t *wcs1 = va_arg(args, const wchar_t *);
>  		const wchar_t *wcs2 = va_arg(args, const wchar_t *);
> @@ -801,6 +809,7 @@ void clar__assert_equal(
>  			}
>  		}
>  	}
> +#endif // HAVE_WCHAR
>  	else if (!strcmp("%"PRIuMAX, fmt) || !strcmp("%"PRIxMAX, fmt)) {
>  		uintmax_t sz1 = va_arg(args, uintmax_t), sz2 = va_arg(args, uintmax_t);
>  		is_equal = (sz1 == sz2);
> 

Hi,

On Buildroot site, Edgar Bonet (Cc:'ed) suggests to improve your patch by
wrapping strcmps [1]:

---- >8 ----
diff --git a/t/unit-tests/clar/clar.c b/t/unit-tests/clar/clar.c
index cef0f023c2..6de0b415b1 100644
--- a/t/unit-tests/clar/clar.c
+++ b/t/unit-tests/clar/clar.c
@@ -18,6 +18,13 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_WCHAR__)
+   /* uClibc can be built without wchar support, in which case the
+      installed <wchar.h> is a stub that does not define wchar_t. */
+#else
+#  define HAVE_WCHAR
+#endif
+
 #ifdef _WIN32
 #	define WIN32_LEAN_AND_MEAN
 #	include <windows.h>
@@ -763,6 +770,7 @@ void clar__assert_equal(
 			}
 		}
 	}
+#ifdef HAVE_WCHAR
 	else if (!strcmp("%ls", fmt)) {
 		const wchar_t *wcs1 = va_arg(args, const wchar_t *);
 		const wchar_t *wcs2 = va_arg(args, const wchar_t *);
@@ -798,6 +806,7 @@ void clar__assert_equal(
 			}
 		}
 	}
+#endif // HAVE_WCHAR
 	else if (!strcmp("%"PRIuZ, fmt) || !strcmp("%"PRIxZ, fmt)) {
 		size_t sz1 = va_arg(args, size_t), sz2 = va_arg(args, size_t);
 		is_equal = (sz1 == sz2);

Thanks.

[1]: https://lore.kernel.org/buildroot/f517190c-6fcd-4101-afa6-f6ea521feb9e@grenoble.cnrs.fr/

-- 
An old man doll... just what I always wanted! - Clara

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