diff --git a/CMakeLists.txt b/CMakeLists.txt
index c188f30..d1d176b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -268,6 +268,8 @@
   add_definitions("-DSERF_TEST_DEFLATE_4GBPLUS_BUCKETS")
 endif()
 
+# Define OPENSSL_NO_STDIO to prevent using _fp() API.
+add_definitions("-DOPENSSL_NO_STDIO")
 
 # Set common compiler flags
 if(NOT MSVC)
diff --git a/SConstruct b/SConstruct
index a40128f..d94d493 100644
--- a/SConstruct
+++ b/SConstruct
@@ -336,6 +336,9 @@
 lib_static = env.StaticLibrary(LIBNAME, SOURCES)
 lib_shared = env.SharedLibrary(SHLIBNAME, SOURCES + SHARED_SOURCES)
 
+# Define OPENSSL_NO_STDIO to prevent using _fp() API.
+env.Append(CPPDEFINES=['OPENSSL_NO_STDIO'])
+
 if aprstatic:
   env.Append(CPPDEFINES=['APR_DECLARE_STATIC', 'APU_DECLARE_STATIC'])