Backported FMT_STRING

include/spdlog/common.h

@@ -43,11 +43,13 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT) && FMT_VERSION >= 80000  // backward compatibility with fmt versions older than 8
     #define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
+    #define SPDLOG_FMT_STRING(format_string) FMT_STRING(format_string)
     #if defined(SPDLOG_WCHAR_FILENAMES)
         #include "fmt/xchar.h"
     #endif
 #else
     #define SPDLOG_FMT_RUNTIME(format_string) format_string
+    #define SPDLOG_FMT_STRING(format_string) format_string
 #endif
 
 #ifndef SPDLOG_FUNCTION

include/spdlog/details/fmt_helper.h

@@ -88,7 +88,7 @@ inline void pad2(int n, memory_buf_t &dest) {
         dest.push_back(static_cast<char>('0' + n % 10));
     } else  // unlikely, but just in case, let fmt deal with it
     {
-        fmt_lib::format_to(std::back_inserter(dest), "{:02}", n);
+        fmt_lib::format_to(std::back_inserter(dest), SPDLOG_FMT_STRING("{:02}"), n);
     }
 }
 

include/spdlog/fmt/bin_to_hex.h

@@ -211,7 +211,7 @@ struct formatter<spdlog::details::dump_info<T>, char> {
         *inserter++ = '\n';
 
         if (put_positions) {
-            spdlog::fmt_lib::format_to(inserter, "{:04X}: ", pos);
+            spdlog::fmt_lib::format_to(inserter, SPDLOG_FMT_STRING("{:04X}: "), pos);
         }
     }
 };

include/spdlog/logger.h

@@ -25,7 +25,7 @@
     #define SPDLOG_LOGGER_CATCH(location)                                                                  \
         catch (const std::exception &ex) {                                                                 \
             if (!location.empty()) {                                                                       \
-                err_handler_(fmt_lib::format("{} [{}({})]", ex.what(), location.filename, location.line)); \
+                err_handler_(fmt_lib::format(SPDLOG_FMT_STRING("{} [{}({})]"), ex.what(), location.filename, location.line)); \
             } else {                                                                                       \
                 err_handler_(ex.what());                                                                   \
             }                                                                                              \

include/spdlog/sinks/daily_file_sink.h

@@ -29,7 +29,7 @@ struct daily_filename_calculator {
     static filename_t calc_filename(const filename_t &filename, const tm &now_tm) {
         filename_t basename, ext;
         std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-        return fmt_lib::format(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
+        return fmt_lib::format(SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}")), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1,
                                now_tm.tm_mday, ext);
     }
 };

src/sinks/rotating_file_sink.cpp

@@ -51,7 +51,7 @@ filename_t rotating_file_sink<Mutex>::calc_filename(const filename_t &filename,
 
     filename_t basename, ext;
     std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-    return fmt_lib::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+    return fmt_lib::format(SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}.{}{}")), basename, index, ext);
 }
 
 template <typename Mutex>