fix path_from_handle implementation on Windows

Refs: apolukhin#57
Firefly35 · Sep 1, 2022 · cbb49f8 · cbb49f8
1 parent 9f9471c
commit cbb49f8
Showing 1 changed file with 10 additions and 9 deletions.
diff --git a/include/boost/dll/detail/windows/path_from_handle.hpp b/include/boost/dll/detail/windows/path_from_handle.hpp
@@ -31,27 +31,28 @@ namespace boost { namespace dll { namespace detail {
         BOOST_STATIC_CONSTANT(boost::winapi::DWORD_, ERROR_INSUFFICIENT_BUFFER_ = 0x7A);
         BOOST_STATIC_CONSTANT(boost::winapi::DWORD_, DEFAULT_PATH_SIZE_ = 260);
 
-        // On success, GetModuleFileNameW() doesn't reset last error to ERROR_SUCCESS. Resetting it manually.
-        boost::winapi::GetLastError();
-
         // If `handle` parameter is NULL, GetModuleFileName retrieves the path of the
         // executable file of the current process.
         boost::winapi::WCHAR_ path_hldr[DEFAULT_PATH_SIZE_];
-        boost::winapi::GetModuleFileNameW(handle, path_hldr, DEFAULT_PATH_SIZE_);
-        ec = boost::dll::detail::last_error_code();
-        if (!ec) {
+        const boost::winapi::DWORD_ ret = boost::winapi::GetModuleFileNameW(handle, path_hldr, DEFAULT_PATH_SIZE_);
+        if (ret) {
+            // On success, GetModuleFileNameW() doesn't reset last error to ERROR_SUCCESS. Resetting it manually.
+            ec.clear();
             return boost::dll::fs::path(path_hldr);
         }
 
+        ec = boost::dll::detail::last_error_code();
         for (unsigned i = 2; i < 1025 && static_cast<boost::winapi::DWORD_>(ec.value()) == ERROR_INSUFFICIENT_BUFFER_; i *= 2) {
             std::wstring p(DEFAULT_PATH_SIZE_ * i, L'\0');
             const std::size_t size = boost::winapi::GetModuleFileNameW(handle, &p[0], DEFAULT_PATH_SIZE_ * i);
-            ec = boost::dll::detail::last_error_code();
-
-            if (!ec) {
+            if (size) {
+                // On success, GetModuleFileNameW() doesn't reset last error to ERROR_SUCCESS. Resetting it manually.
+                ec.clear();
                 p.resize(size);
                 return boost::dll::fs::path(p);
             }
+
+            ec = boost::dll::detail::last_error_code();
         }
 
         // Error other than ERROR_INSUFFICIENT_BUFFER_ occurred or failed to allocate buffer big enough.