Fix #1675

include/spdlog/sinks/stdout_sinks-inl.h

@@ -11,6 +11,15 @@
 #include <spdlog/pattern_formatter.h>
 #include <memory>
 
+#ifdef _WIN32
+// under windows using fwrite to non-binary stream results in \r\r\n (see issue #1675)
+// so instead we use ::FileWrite
+#include <spdlog/details/windows_include.h>
+#include <fileapi.h> // WriteFile (..)
+#include <io.h>      // _get_osfhandle(..)
+#include <stdio.h>   // _fileno(..)
+#endif               // WIN32
+
 namespace spdlog {
 
 namespace sinks {
@@ -20,7 +29,16 @@ SPDLOG_INLINE stdout_sink_base<ConsoleMutex>::stdout_sink_base(FILE *file)
     : mutex_(ConsoleMutex::mutex())
     , file_(file)
     , formatter_(details::make_unique<spdlog::pattern_formatter>())
-{}
+{
+#ifdef _WIN32
+    // get windows handle from the FILE* object
+    handle_ = (HANDLE)::_get_osfhandle(::_fileno(file_));
+    if (handle_ == INVALID_HANDLE_VALUE)
+    {
+        throw_spdlog_ex("spdlog::stdout_sink_base: _get_osfhandle() failed", errno);
+    }
+#endif // WIN32
+}
 
 template<typename ConsoleMutex>
 SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::log(const details::log_msg &msg)
@@ -28,8 +46,14 @@ SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::log(const details::log_msg &m
     std::lock_guard<mutex_t> lock(mutex_);
     memory_buf_t formatted;
     formatter_->format(msg, formatted);
-    fwrite(formatted.data(), sizeof(char), formatted.size(), file_);
+#ifdef _WIN32
-    fflush(file_); // flush every line to terminal
+    auto size = static_cast<DWORD>(formatted.size());
+    DWORD bytes_written = 0;
+    ::WriteFile(handle_, formatted.data(), size, &bytes_written, nullptr);
+#else
+    ::fwrite(formatted.data(), sizeof(char), formatted.size(), file_);
+    ::fflush(file_); // flush every line to terminal
+#endif // WIN32    
 }
 
 template<typename ConsoleMutex>

include/spdlog/sinks/stdout_sinks.h

@@ -7,6 +7,7 @@
 #include <spdlog/details/synchronous_factory.h>
 #include <spdlog/sinks/sink.h>
 #include <cstdio>
+#include <spdlog/details/windows_include.h>
 
 namespace spdlog {
 
@@ -36,6 +37,9 @@ protected:
     mutex_t &mutex_;
     FILE *file_;
     std::unique_ptr<spdlog::formatter> formatter_;
+#ifdef _WIN32
+    HANDLE handle_;    
+#endif // WIN32
 };
 
 template<typename ConsoleMutex>