diff --git a/src/proof/cec/cecCec.c b/src/proof/cec/cecCec.c
index e881c53be..f01df4df4 100644
--- a/src/proof/cec/cecCec.c
+++ b/src/proof/cec/cecCec.c
@@ -24,17 +24,16 @@
 #include "misc/extra/extra.h"
 #include "sat/cnf/cnf.h"
 
-void Abc_NtkVerifyPrintCex( const int * pModel, const int * pValues1, const int * pValues2, 
-    const char * const * ppInputNames, int nInputs, const char * const * ppOutputNames, int nOutputs, 
-    const char * pNtkName1, const char * pNtkName2 );
-
 ABC_NAMESPACE_IMPL_START
 
-
 ////////////////////////////////////////////////////////////////////////
 ///                        DECLARATIONS                              ///
 ////////////////////////////////////////////////////////////////////////
 
+extern void Abc_NtkVerifyPrintCex( const int * pModel, const int * pValues1, const int * pValues2, 
+    const char * const * ppInputNames, int nInputs, const char * const * ppOutputNames, int nOutputs, 
+    const char * pNtkName1, const char * pNtkName2 );
+
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////