diff --git a/Pdf4QtLibCore/sources/pdfccittfaxdecoder.cpp b/Pdf4QtLibCore/sources/pdfccittfaxdecoder.cpp
index 3750601..b5397c1 100644
--- a/Pdf4QtLibCore/sources/pdfccittfaxdecoder.cpp
+++ b/Pdf4QtLibCore/sources/pdfccittfaxdecoder.cpp
@@ -28,7 +28,7 @@ namespace pdf
 {
 
 template<char... Digits>
-constexpr uint8_t operator "" _bitlength()
+constexpr uint8_t operator ""_bitlength()
 {
     return sizeof...(Digits);
 }