Fixed wchar support under msvc

include/spdlog/common.h

@@ -35,6 +35,10 @@
 
 #include <spdlog/fmt/fmt.h>
 
+#if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+#    include <spdlog/fmt/xchar.h>
+#endif
+
 // visual studio upto 2013 does not support noexcept nor constexpr
 #if defined(_MSC_VER) && (_MSC_VER < 1900)
 #    define SPDLOG_NOEXCEPT _NOEXCEPT

include/spdlog/fmt/xchar.h

@@ -0,0 +1,20 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ostream support
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#ifdef SPDLOG_HEADER_ONLY
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#endif
+#include <spdlog/fmt/bundled/xchar.h>
+#else
+#include <fmt/xchar.h>
+#endif

include/spdlog/sinks/daily_file_sink.h

@@ -50,7 +50,11 @@ struct daily_filename_format_calculator
     {
         // generate fmt datetime format string, e.g. {:%Y-%m-%d}.
         filename_t fmt_filename = fmt::format(SPDLOG_FILENAME_T("{{:{}}}"), filename);
+#if defined(_MSC_VER) && defined(SPDLOG_WCHAR_FILENAMES) // for some reason msvc doesnt allow fmt::runtime(..) with wchar here
+        return fmt::format(fmt_filename, now_tm);
+#else
         return fmt::format(fmt::runtime(fmt_filename), now_tm);
+#endif
     }
 };