diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index 111caac..36983e0 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -66,7 +66,7 @@ std::string valueToString( Value::UInt value )
 std::string valueToString( double value )
 {
    char buffer[32];
-#ifdef __STDC_SECURE_LIB__ // Use secure version with visual studio 2005 to avoid warning.
+#if defined(_MSC_VER) && defined(__STDC_SECURE_LIB__) // Use secure version with visual studio 2005 to avoid warning. 
    sprintf_s(buffer, sizeof(buffer), "%#.16g", value); 
 #else	
    sprintf(buffer, "%#.16g", value);