doesn't compile

[folkertvanheusden]

/home/folkert/Projects2/libego/source/gtp/gtp.cpp: In member function ‘bool Gtp::Io::IsEmpty()’:
/home/folkert/Projects2/libego/source/gtp/gtp.cpp:42:13: error: cannot convert ‘std::istringstream’ {aka ‘std::__cxx11::basic_istringstream<char>’} to ‘bool’ in initialization
   42 |   bool ok = in;
      |             ^~
      |             |
      |             std::istringstream {aka std::__cxx11::basic_istringstream<char>}
make[2]: *** [gtp/CMakeFiles/gtp.dir/build.make:82: gtp/CMakeFiles/gtp.dir/gtp.cpp.o] Error 1

I propose the following (untested, it compiles though):

index 58dde30..9712241 100644
--- a/source/gtp/gtp.cpp
+++ b/source/gtp/gtp.cpp
@@ -39,10 +39,10 @@ bool Io::IsEmpty() {
   string s;
   std::streampos pos = in.tellg();
   in >> s;
-  bool ok = in;
+  bool ok = s.empty();
   in.seekg(pos);
   in.clear();
-  return !ok;
+  return ok;
 }
 
 void Io::PrepareIn () {