diff --git a/Foundation/src/Base32Decoder.cpp b/Foundation/src/Base32Decoder.cpp
index 8d6be3ecd..135269037 100644
--- a/Foundation/src/Base32Decoder.cpp
+++ b/Foundation/src/Base32Decoder.cpp
@@ -171,7 +171,9 @@ Base32DecoderBuf* Base32DecoderIOS::rdbuf()
 
 Base32Decoder::Base32Decoder(std::istream& istr): Base32DecoderIOS(istr), std::istream(&_buf)
 {
+#ifdef POCO_OS_FAMILY_WINDOWS
 	unsetf(std::ios_base::skipws);
+#endif
 }
 
 
diff --git a/Foundation/src/Base64Decoder.cpp b/Foundation/src/Base64Decoder.cpp
index decd6b41f..b9c4be3d9 100644
--- a/Foundation/src/Base64Decoder.cpp
+++ b/Foundation/src/Base64Decoder.cpp
@@ -147,7 +147,9 @@ Base64DecoderBuf* Base64DecoderIOS::rdbuf()
 
 Base64Decoder::Base64Decoder(std::istream& istr): Base64DecoderIOS(istr), std::istream(&_buf)
 {
+#ifdef POCO_OS_FAMILY_WINDOWS
 	unsetf(std::ios_base::skipws);
+#endif
 }