Log to stderr instead of stdout (#1285)

ConsoleAppender is writing logging output to stdout.
In POSIX systems, logging should always go to stderr,
and logging to stdout will cause problems for applications
that have regular data output.

Resolves: #1286

Signed-off-by: Christian Ocker <[email protected]>

Author: fermeise

olp-cpp-sdk-core/src/logging/ConsoleAppender.cpp

@@ -75,7 +75,7 @@ IAppender& ConsoleAppender::append(const LogMessage& message) {
 #ifdef PORTING_PLATFORM_ANDROID
   android_append_in_chunks(message.level, message.tag, formattedMessage);
 #else
-  std::cout << formattedMessage << std::endl;
+  std::clog << formattedMessage << std::endl;
 #endif
   return *this;
 }

olp-cpp-sdk-core/tests/logging/LogTest.cpp

@@ -154,9 +154,9 @@ TEST(LogTest, DifferentLevelsForConsoleAndFileLogging) {
   }
   olp::logging::Log::setLevel(olp::logging::Level::Trace);
 
-  // redirecting cout to stringstream
+  // redirecting clog to stringstream
   std::stringstream string_stream;
-  auto default_cout_buffer = std::cout.rdbuf(string_stream.rdbuf());
+  auto default_clog_buffer = std::clog.rdbuf(string_stream.rdbuf());
 
   OLP_SDK_LOG_INFO("info", "Info "
                                << "message");
@@ -169,8 +169,8 @@ TEST(LogTest, DifferentLevelsForConsoleAndFileLogging) {
   OLP_SDK_LOG_FATAL("fatal", "Fatal "
                                  << "message");
 
-  // resetting cout
-  std::cout.rdbuf(default_cout_buffer);
+  // resetting clog
+  std::clog.rdbuf(default_clog_buffer);
 
   // Clear out configuration so the file file handles are closed.
   olp::logging::Log::configure(olp::logging::Configuration::createDefault());