7.5

1 files changed, 16 insertions, 7 deletions

diff --git a/zen/file_error.h b/zen/file_error.h
index d8c6224c..7be52282 100644
--- a/zen/file_error.h
+++ b/zen/file_error.h
@@ -36,14 +36,23 @@ DEFINE_NEW_FILE_ERROR(ErrorFileLocked);
 DEFINE_NEW_FILE_ERROR(ErrorDifferentVolume);
 
 
-//CAVEAT: evalulate global error code *before* "throw" statement which may overwrite error code
-//due to a memory allocation before it creates the thrown instance! (e.g. affects MinGW + Win XP!!!)
-template <class FE = FileError> inline
-void throwFileError(const std::wstring& msg, const std::wstring& functionName, const ErrorCode ec) //throw FileError
-{
-    throw FE(msg, formatSystemError(functionName, ec));
-}
+//CAVEAT: thread-local Win32 error code is easily overwritten => evaluate *before* making any (indirect) system calls:
+//-> MinGW + Win XP: "throw" statement allocates memory to hold the exception object => error code is cleared
+//-> VC 2015, Debug: std::wstring allocator internally calls ::FlsGetValue()         => error code is cleared
+#ifdef _MSC_VER
+#define THROW_LAST_FILE_ERROR(msg, functionName)                           \
+    do                                                                     \
+    {                                                                      \
+        const ErrorCode ecInternal = getLastError();                       \
+        throw FileError(msg, formatSystemError(functionName, ecInternal)); \
+        \
+        __pragma(warning(suppress: 4127)) /*"conditional expression is constant"*/ \
+    } while (false)
 
+#else //variant witout "__pragma":
+#define THROW_LAST_FILE_ERROR(msg, functionName)                           \
+    do { const ErrorCode ecInternal = getLastError(); throw FileError(msg, formatSystemError(functionName, ecInternal)); } while (false)
+#endif
 
 //----------- facilitate usage of std::wstring for error messages --------------------