Checking for a return value with FormatMessage; if the call fails, there's no guarantee that the buffer will be non-null.
llvm-svn: 195019
diff --git a/llvm/lib/Support/Windows/Windows.h b/llvm/lib/Support/Windows/Windows.h
index 657ae4f..1f3417d 100644
--- a/llvm/lib/Support/Windows/Windows.h
+++ b/llvm/lib/Support/Windows/Windows.h
@@ -39,11 +39,16 @@
if (!ErrMsg)
return true;
char *buffer = NULL;
- FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,
- NULL, GetLastError(), 0, (LPSTR)&buffer, 1, NULL);
- *ErrMsg = prefix + buffer;
+ DWORD R = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+ FORMAT_MESSAGE_FROM_SYSTEM,
+ NULL, GetLastError(), 0, (LPSTR)&buffer, 1, NULL);
+ if (R)
+ *ErrMsg = prefix + buffer;
+ else
+ *ErrMsg = prefix + "Unknown error";
+
LocalFree(buffer);
- return true;
+ return R != 0;
}
template <typename HandleTraits>