fixed a bug of not checking the return value of wcrtomb properly in qse_wcrtomb().

fixed a bug of passing a wrong buffer to qse_wcrtomb() in qse_wcsntombsn().
enhanced qse_tio_writembsn() and qse_tio_writewcsn()

qse/samples/cmn/sio02.c

@@ -0,0 +1,97 @@
+#include <qse/cmn/stdio.h>
+#include <qse/cmn/sio.h>
+
+#include <locale.h>
+
+#if defined(_WIN32)
+#	include <windows.h>
+#endif
+
+#define R(f) \
+	do { \
+		qse_printf (QSE_T("== %s ==\n"), QSE_T(#f)); \
+		if (f() == -1) return -1; \
+	} while (0)
+
+static int test1 (void)
+{
+	const qse_wchar_t unistr[] = 
+	{
+		/* ugly hack for old compilers that don't support \u */
+		/*L"\uB108 \uBB50\uAC00 \uC798\uB0AC\uC5B4?",*/
+		0xB108,
+		L' ',
+		0xBB50,
+		0xAC00,
+		L' ',
+		0xC798,
+		0xB0AC,
+		0xC5B4,
+		L'?',
+		L'\0'
+	};
+
+	const qse_wchar_t unistr2[] = 
+	{
+		/* this include an illegal unicode character.
+		 * a strict converter should return an error so a question mark 
+		 * should be printed for such a character */
+		0xFFFF53C0u,
+		0xFFFF4912u,
+		0xBA00u,
+		0xFFFF1234u,
+		L'\0'
+	};
+	const qse_wchar_t* x[] =
+	{
+		L"",
+		L"",
+		L"",
+		L"Fly to the universe, kick your ass"
+	};
+	int i;
+	qse_sio_t* sio;
+
+	x[1] = unistr;
+	x[2] = unistr2;
+
+	sio = qse_sio_openstd (QSE_NULL, 0, QSE_SIO_STDOUT, QSE_SIO_READ | QSE_SIO_IGNOREMBWCERR | QSE_SIO_NOAUTOFLUSH);
+	if (sio == QSE_NULL) return -1;
+
+	for (i = 0; i < QSE_COUNTOF(x); i++)
+	{
+		qse_sio_putws (sio, x[i]);
+		qse_sio_putws (sio, QSE_WT("\n"));
+	}
+
+	qse_sio_close (sio);
+	return 0;
+}
+
+int main ()
+{
+#if defined(_WIN32)
+	char codepage[100];
+	UINT old_cp = GetConsoleOutputCP();
+	SetConsoleOutputCP (CP_UTF8);
+
+	/* TODO: on windows this set locale only affects those mbcs fucntions in clib.
+	 * it doesn't support utf8 i guess find a working way. the following won't work 
+	sprintf (codepage, ".%d", GetACP());
+	setlocale (LC_ALL, codepage);
+	*/
+#else
+	setlocale (LC_ALL, "");
+#endif
+
+	qse_printf (QSE_T("--------------------------------------------------------------------------------\n"));
+	qse_printf (QSE_T("Set the environment LANG to a Unicode locale such as UTF-8 if you see the illegal XXXXX errors. If you see such errors in Unicode locales, this program might be buggy. It is normal to see such messages in non-Unicode locales as it uses Unicode data\n"));
+	qse_printf (QSE_T("--------------------------------------------------------------------------------\n"));
+
+	R (test1);
+
+#if defined(_WIN32)
+	SetConsoleOutputCP (old_cp);
+#endif
+	return 0;
+}