Use different logic to get registry key.

Author: kpeeters

README.rst

@@ -388,7 +388,7 @@ warned, it can easily take several hours, but at least it's automatic)::
   
     vcpkg install mpir:x64-windows glibmm:x64-windows   (go have a coffee)
     vcpkg install sqlite3:x64-windows boost:x64-windows (go for dinner)
-    vcpkg install gtkmm:x64-windows winreg:x64-windows  (run overnight)
+    vcpkg install gtkmm:x64-windows  (run overnight)
     vcpkg integrate install
 
 boost-system:x64-windows

client_server/cadabra-server.cc

@@ -6,7 +6,33 @@
 
 #ifdef _WIN32
 #include <Windows.h>
-#include <WinReg.hpp>
+#endif
+
+#ifdef _WIN32
+
+std::string getRegKey(const std::string& location, const std::string& name)
+	{
+	HKEY key;
+	TCHAR value[1024]; 
+	DWORD bufLen = 1024*sizeof(TCHAR);
+	long ret;
+	ret = RegOpenKeyExA(HKEY_CURRENT_USER, location.c_str(), 0, KEY_QUERY_VALUE, &key);
+	if( ret != ERROR_SUCCESS ){
+		return std::string();
+		}
+	ret = RegQueryValueExA(key, name.c_str(), 0, 0, (LPBYTE) value, &bufLen);
+	RegCloseKey(key);
+	if ( (ret != ERROR_SUCCESS) || (bufLen > 1024*sizeof(TCHAR)) ){
+		return std::string();
+		}
+	std::string stringValue = std::string(value, (size_t)bufLen - 1);
+	size_t i = stringValue.length();
+	while( i > 0 && stringValue[i-1] == '\0' ){
+		--i;
+		}
+	return stringValue.substr(0,i); 
+	}
+
 #endif
 
 // Run a simple Cadabra server on a local port.
@@ -19,9 +45,8 @@ int main()
 	// by querying a registry key.
 	std::string pythonhome=Glib::getenv("PYTHONHOME");
 	std::string pythonpath=Glib::getenv("PYTHONPATH");
-	
-	winreg::RegKey  key{ winreg::HKEY_CURRENT_USER, L"SOFTWARE\\Python\\PythonCore\\3.7" };
-	std::wstring s  = key.GetStringValue(L"");
+
+	std::string s = getRegKey("SOFTWARE\\Python\\PythonCore\\3.7", "");
 
 //	Glib::setenv("PYTHONHOME", (pythonhome.size()>0)?(pythonhome+":"):"" + Glib::get_home_dir()+"/Anaconda3");
 //	Glib::setenv("PYTHONPATH", (pythonpath.size()>0)?(pythonpath+":"):"" + Glib::get_home_dir()+"/Anaconda3");