fix: flushing stdout after sending UCI responses (#345) (#350)

Author: benthevining

ben-bot/src/main.cpp

@@ -17,7 +17,6 @@
 #include <cstdlib>
 #include <exception>
 #include <format>
-#include <ios>
 #include <libchess/uci/Printing.hpp>
 #include <libchess/util/Console.hpp>
 
@@ -27,10 +26,6 @@ int main(const int argc, const char** argv)
 try {
     chess::util::enable_utf8_console_output();
 
-    // we don't care about the ability to intermix C stdio with C++ iostreams
-    // all of our IO is done through C++ iostreams
-    std::ios_base::sync_with_stdio(false);
-
     const auto args = ben_bot::Arguments::parse(argc, argv);
 
     ben_bot::Engine engine;

libchess/src/uci/EngineBase.cpp

@@ -53,6 +53,7 @@ void EngineBase::handle_command(std::string_view command)
             wait();
 
         println("readyok");
+        std::cout.flush();
         return;
     }
 
@@ -123,6 +124,8 @@ void EngineBase::respond_to_uci()
         println("{}", option->get_declaration_string());
 
     println("uciok");
+
+    std::cout.flush();
 }
 
 void EngineBase::handle_setpos(const string_view arguments)

libchess/src/uci/Printing.cpp

@@ -48,7 +48,7 @@ void best_move(
         "bestmove {}{}",
         to_uci(bestMove), ponder_move_string(ponderMove));
 
-    std::cout.flush(); // make sure the GUI doesn't think we've stalled
+    std::cout.flush();
 }
 
 namespace {