/*****************************************************************************/ /*! * \file c_interface.h * * Authors: Clark Barrett * Cristian Cadar * * Created: Thu Jun 5 10:34:02 2003 * *
* * License to use, copy, modify, sell and/or distribute this software * and its documentation for any purpose is hereby granted without * royalty, subject to the terms and conditions defined in the \ref * COPYING file provided with this distribution. * *
* */ /*****************************************************************************/ #include "cvc4_public.h" #ifndef _cvc3__include__c_interface_h_ #define _cvc3__include__c_interface_h_ #include "bindings/compat/c/c_interface_defs.h" //! Flags can be NULL VC vc_createValidityChecker(Flags flags); //! Create validity checker's flags Flags vc_createFlags(); //! Destroy the validity checker. /*! Must be called after all other objects are deleted, except the flags */ void vc_destroyValidityChecker(VC vc); //! Delete the flags void vc_deleteFlags(Flags flags); //! Delete type void vc_deleteType(Type t); //! Delete expression void vc_deleteExpr(Expr e); //! Delete operator void vc_deleteOp(Op op); //! Delete vector of expressions void vc_deleteVector(Expr* e); //! Delete vector of types void vc_deleteTypeVector(Type* e); // Setting the flags //! Set a boolean flag to true or false void vc_setBoolFlag(Flags flags, char* name, int val); //! Set an integer flag to the given value void vc_setIntFlag(Flags flags, char* name, int val); //! Set a string flag to the given value void vc_setStringFlag(Flags flags, char* name, char* val); //! Add a (string, bool) pair to the multy-string flag void vc_setStrSeqFlag(Flags flags, char* name, char* str, int val); // Basic types Type vc_boolType(VC vc); Type vc_realType(VC vc); Type vc_intType(VC vc); //! Create a subrange type Type vc_subRangeType(VC vc, int lowerEnd, int upperEnd); //! Creates a subtype defined by the given predicate /*! * \param vc the validity checker * * \param pred is a predicate taking one argument of type T and returning * Boolean. The resulting type is a subtype of T whose elements x are those * satisfying the predicate pred(x). * * \param witness is an expression of type T for which pred holds (if a Null * expression is passed as a witness, cvc will try to prove \f$\exists x. pred(x))\f$. * if the witness check fails, a TypecheckException is thrown. */ Type vc_subtypeType(VC vc, Expr pred, Expr witness); // Tuple types Type vc_tupleType2(VC vc, Type type0, Type type1); Type vc_tupleType3(VC vc, Type type0, Type type1, Type type2); //! Create a tuple type. 'types' is an array of types of length numTypes. Type vc_tupleTypeN(VC vc, Type* types, int numTypes); // Record types Type vc_recordType1(VC vc, char* field, Type type); Type vc_recordType2(VC vc, char* field0, Type type0, char* field1, Type type1); Type vc_recordType3(VC vc, char* field0, Type type0, char* field1, Type type1, char* field2, Type type2); //! Create a record type. /*! 'fields' and 'types' are arrays of length numFields. */ Type vc_recordTypeN(VC vc, char** fields, Type* types, int numFields); // Datatypes //! Single datatype, single constructor /*! The types are either type exressions (obtained from a type with * getExpr()) or string expressions containing the name of (one of) the * dataType(s) being defined. */ Type vc_dataType1(VC vc, char* name, char* constructor, int arity, char** selectors, Expr* types); //! Single datatype, multiple constructors /*! The types are either type exressions (obtained from a type with * getExpr()) or string expressions containing the name of (one of) the * dataType(s) being defined. */ Type vc_dataTypeN(VC vc, char* name, int numCons, char** constructors, int* arities, char*** selectors, Expr** types); //! Multiple datatypes /*! The types are either type exressions (obtained from a type with * getExpr()) or string expressions containing the name of (one of) the * dataType(s) being defined. * Returns an array of size numTypes which must be freed by calling * vc_deleteTypeVector. */ Type* vc_dataTypeMN(VC vc, int numTypes, char** names, int* numCons, char*** constructors, int** arities, char**** selectors, Expr*** types); //! Create an array type Type vc_arrayType(VC vc, Type typeIndex, Type typeData); //! Create a bitvector type of length n Type vc_bvType(VC vc, int n); //! Create a function type with 1 argument Type vc_funType1(VC vc, Type a1, Type typeRan); //! Create a function type with 2 arguments Type vc_funType2(VC vc, Type a1, Type a2, Type typeRan); //! Create a function type with 3 arguments Type vc_funType3(VC vc, Type a1, Type a2, Type a3, Type typeRan); //! Create a function type with N arguments Type vc_funTypeN(VC vc, Type* args, Type typeRan, int numArgs); // User-defined types //! Create an uninterpreted named type Type vc_createType(VC vc, char* typeName); //! Lookup a user-defined (uninterpreted) type by name Type vc_lookupType(VC vc, char* typeName); ///////////////////////////////////////////////////////////////////////////// // Expr manipulation methods // ///////////////////////////////////////////////////////////////////////////// //! Return the ExprManager ExprManager* vc_getEM(VC vc); //! Create a variable with a given name and type /*! The type cannot be a function type. */ Expr vc_varExpr(VC vc, char* name, Type type); //! Create a variable with a given name, type, and value Expr vc_varExprDef(VC vc, char* name, Type type, Expr def); //! Get the expression and type associated with a name. /*! If there is no such Expr, a NULL Expr is returned. */ Expr vc_lookupVar(VC vc, char* name, Type* type); //! Get the type of the Expr. Type vc_getType(VC vc, Expr e); //! Get the largest supertype of the Expr. Type vc_getBaseType(VC vc, Expr e); //! Get the largest supertype of the Type. Type vc_getBaseTypeOfType(VC vc, Type t); //! Get the subtype predicate Expr vc_getTypePred(VC vc, Type t, Expr e); //! Create a string Expr Expr vc_stringExpr(VC vc, char* str); //! Create an ID Expr Expr vc_idExpr(VC vc, char* name); //! Create a list Expr /*! Intermediate representation for DP-specific expressions. * Normally, the first element of the list is a string Expr * representing an operator, and the rest of the list are the * arguments. For example, * * kids.push_back(vc->stringExpr("PLUS")); * kids.push_back(x); // x and y are previously created Exprs * kids.push_back(y); * Expr lst = vc->listExpr(kids); * * Or, alternatively (using its overloaded version): * * Expr lst = vc->listExpr("PLUS", x, y); * * or * * vector summands; * summands.push_back(x); summands.push_back(y); ... * Expr lst = vc->listExpr("PLUS", summands); */ Expr vc_listExpr(VC vc, int numKids, Expr* kids); // Expr I/O //! Expr vc_parseExpr(VC vc, char* s); void vc_printExpr(VC vc, Expr e); //! Print e into a char* /*! Note that the ownership of the char* is given to the caller which should free the memory when it is done with it. This can be done by calling vc_deleteString. */ char* vc_printExprString(VC vc, Expr e); //! Delete char* returned by previous function void vc_deleteString(char* str); //! Print 'e' into an open file descriptor void vc_printExprFile(VC vc, Expr e, int fd); //! Import the Expr from another instance of VC /*! When expressions need to be passed among several instances of * VC, they need to be explicitly imported into the * corresponding instance using this method. The return result is * an identical expression that belongs to the current instance of * VC, and can be safely used as part of more complex * expressions from the same instance. \param vc is the instance to be imported into \param e is the expression created using a different (not vc) instance */ Expr vc_importExpr(VC vc, Expr e); //! Import the Type from another instance of VC /*! \sa vc_importExpr() */ Type vc_importType(Type t); //! Create an equality expression. The two children must have the same type. Expr vc_eqExpr(VC vc, Expr child0, Expr child1); //! Create an all distinct expression. All children must ahve the same type. Expr vc_distinctExpr(VC vc, Expr* children, int numChildren); // Boolean expressions // The following functions create Boolean expressions. The children provided // as arguments must be of type Boolean. Expr vc_trueExpr(VC vc); Expr vc_falseExpr(VC vc); Expr vc_notExpr(VC vc, Expr child); Expr vc_andExpr(VC vc, Expr left, Expr right); Expr vc_andExprN(VC vc, Expr* children, int numChildren); Expr vc_orExpr(VC vc, Expr left, Expr right); Expr vc_orExprN(VC vc, Expr* children, int numChildren); Expr vc_impliesExpr(VC vc, Expr hyp, Expr conc); Expr vc_iffExpr(VC vc, Expr left, Expr right); Expr vc_iteExpr(VC vc, Expr ifpart, Expr thenpart, Expr elsepart); // Substitution // Substitutes oldTerms for newTerms in e. // This function doesn't actually exist in ValidityChecker interface, // but it does in Expr, and its functionality is needed in the C interface. // For consistency, it is represented here as if it were in ValidityChecker. Expr vc_substExpr(VC vc, Expr e, Expr* oldTerms, int numOldTerms, Expr* newTerms, int numNewTerms); // User-defined (uninterpreted) functions. //! Create an operator from a function with a given name and type. /*! Name is given as an ID Expr, and the type must be a function type. */ Op vc_createOp(VC vc, char* name, Type type); //! Create a named user-defined function with a given type Op vc_createOpDef(VC vc, char* name, Type type, Expr def); //! Lookup an operator by name. /*! Returns the operator and the type if the operator exists. * Returns NULL otherwise */ Op vc_lookupOp(VC vc, char* name, Type* type); //! Create expressions with a user-defined operator. /*! op must have a function type. */ Expr vc_funExpr1(VC vc, Op op, Expr child); Expr vc_funExpr2(VC vc, Op op, Expr left, Expr right); Expr vc_funExpr3(VC vc, Op op, Expr child0, Expr child1, Expr child2); Expr vc_funExprN(VC vc, Op op, Expr* children, int numChildren); // Arithmetic //! Create a rational number with numerator n and denominator d. /*! d cannot be 0. */ Expr vc_ratExpr(VC vc, int n, int d); //! Create a rational number n/d; n and d are given as strings /*! n and d are converted to arbitrary-precision integers according to * the given base. d cannot be 0. */ Expr vc_ratExprFromStr(VC vc, char* n, char* d, int base); //! Create a rational from a single string. /*! \param vc the validity checker \param n can be a string containing an integer, a pair of integers "nnn/ddd", or a number in the fixed or floating point format. \param base is the base in which to interpret the string. */ Expr vc_ratExprFromStr1(VC vc, char* n, int base); //! Unary minus. Child must have a numeric type. Expr vc_uminusExpr(VC vc, Expr child); // plus, minus, mult. Children must have numeric types. Expr vc_plusExpr(VC vc, Expr left, Expr right); Expr vc_plusExprN(VC vc, Expr* children, int numChildren); Expr vc_minusExpr(VC vc, Expr left, Expr right); Expr vc_multExpr(VC vc, Expr left, Expr right); Expr vc_powExpr(VC vc, Expr pow, Expr base); Expr vc_divideExpr(VC vc, Expr numerator, Expr denominator); // The following functions create less-than, less-than or equal, // greater-than, and greater-than or equal expressions of type Boolean. // Their arguments must be of numeric types. Expr vc_ltExpr(VC vc, Expr left, Expr right); Expr vc_leExpr(VC vc, Expr left, Expr right); Expr vc_gtExpr(VC vc, Expr left, Expr right); Expr vc_geExpr(VC vc, Expr left, Expr right); // Records // Create record literals; Expr vc_recordExpr1(VC vc, char* field, Expr expr); Expr vc_recordExpr2(VC vc, char* field0, Expr expr0, char* field1, Expr expr1); Expr vc_recordExpr3(VC vc, char* field0, Expr expr0, char* field1, Expr expr1, char* field2, Expr expr2); Expr vc_recordExprN(VC vc, char** fields, Expr* exprs, int numFields); //! Create an expression representing the selection of a field from a record. Expr vc_recSelectExpr(VC vc, Expr record, char* field); //! Record update; equivalent to "record WITH .field := newValue" Expr vc_recUpdateExpr(VC vc, Expr record, char* field, Expr newValue); // Arrays //! Create an expression for the value of array at the given index Expr vc_readExpr(VC vc, Expr array, Expr index); //! Array update; equivalent to "array WITH [index] := newValue" Expr vc_writeExpr(VC vc, Expr array, Expr index, Expr newValue); // Bitvectors // Additional type constructor Type vc_bv32Type(VC vc); // Bitvector constants Expr vc_bvConstExprFromStr(VC vc, char* binary_repr); Expr vc_bvConstExprFromInt(VC vc, int n_bits, unsigned int value); Expr vc_bv32ConstExprFromInt(VC vc, unsigned int value); Expr vc_bvConstExprFromLL(VC vc, int n_bits, unsigned long value); // Concat and extract Expr vc_bvConcatExpr(VC vc, Expr left, Expr right); Expr vc_bvConcatExprN(VC vc, Expr* children, int numChildren); Expr vc_bvExtract(VC vc, Expr child, int high_bit_no, int low_bit_no); Expr vc_bvBoolExtract(VC vc, Expr child, int bit_no); // Bitwise Boolean operators: Negation, And, Or, Xor Expr vc_bvNotExpr(VC vc, Expr child); Expr vc_bvAndExpr(VC vc, Expr left, Expr right); Expr vc_bvOrExpr(VC vc, Expr left, Expr right); Expr vc_bvXorExpr(VC vc, Expr left, Expr right); // Unsigned bitvector inequalities Expr vc_bvLtExpr(VC vc, Expr left, Expr right); Expr vc_bvLeExpr(VC vc, Expr left, Expr right); Expr vc_bvGtExpr(VC vc, Expr left, Expr right); Expr vc_bvGeExpr(VC vc, Expr left, Expr right); // Signed bitvector inequalities Expr vc_bvSLtExpr(VC vc, Expr left, Expr right); Expr vc_bvSLeExpr(VC vc, Expr left, Expr right); Expr vc_bvSGtExpr(VC vc, Expr left, Expr right); Expr vc_bvSGeExpr(VC vc, Expr left, Expr right); // Sign-extend child to a total of nbits bits Expr vc_bvSignExtend(VC vc, Expr child, int nbits); // Bitvector arithmetic: unary minus, plus, subtract, multiply Expr vc_bvUMinusExpr(VC vc, Expr child); Expr vc_bvPlusExpr(VC vc, int n_bits, Expr left, Expr right); Expr vc_bv32PlusExpr(VC vc, Expr left, Expr right); Expr vc_bvMinusExpr(VC vc, int n_bits, Expr left, Expr right); Expr vc_bv32MinusExpr(VC vc, Expr left, Expr right); Expr vc_bvMultExpr(VC vc, int n_bits, Expr left, Expr right); Expr vc_bv32MultExpr(VC vc, Expr left, Expr right); Expr vc_bvUDivExpr(VC vc, Expr left, Expr right); Expr vc_bvURemExpr(VC vc, Expr left, Expr right); Expr vc_bvSDivExpr(VC vc, Expr left, Expr right); Expr vc_bvSRemExpr(VC vc, Expr left, Expr right); Expr vc_bvSModExpr(VC vc, Expr left, Expr right); // Shift operators Expr vc_bvLeftShiftExpr(VC vc, int sh_amt, Expr child); Expr vc_bvRightShiftExpr(VC vc, int sh_amt, Expr child); Expr vc_bv32LeftShiftExpr(VC vc, int sh_amt, Expr child); Expr vc_bv32RightShiftExpr(VC vc, int sh_amt, Expr child); Expr vc_bvVar32LeftShiftExpr(VC vc, Expr sh_amt, Expr child); Expr vc_bvVar32RightShiftExpr(VC vc, Expr sh_amt, Expr child); Expr vc_bvVar32DivByPowOfTwoExpr(VC vc, Expr child, Expr rhs); /*C pointer support: C interface to support C memory arrays in CVC3 */ Expr vc_bvCreateMemoryArray(VC vc, char * arrayName); Expr vc_bvReadMemoryArray(VC vc, Expr array, Expr byteIndex, int numOfBytes); Expr vc_bvWriteToMemoryArray(VC vc, Expr array, Expr byteIndex, Expr element, int numOfBytes); // Tuples //! Create a tuple expression /*! 'children' is an array of elements of length numChildren */ Expr vc_tupleExprN(VC vc, Expr* children, int numChildren); //! Tuple select; equivalent to "tuple.n", where n is an numeral (e.g. tup.5) Expr vc_tupleSelectExpr(VC vc, Expr tuple, int index); //! Tuple update; equivalent to "tuple WITH index := newValue" Expr vc_tupleUpdateExpr(VC vc, Expr tuple, int index, Expr newValue); // Datatypes //! Datatype constructor expression Expr vc_datatypeConsExpr(VC vc, char* constructor, int numArgs, Expr* args); //! Datatype selector expression Expr vc_datatypeSelExpr(VC vc, char* selector, Expr arg); //! Datatype tester expression Expr vc_datatypeTestExpr(VC vc, char* constructor, Expr arg); // Quantifiers //! Create a bound variable. /*! \param vc the validity checker * \param name * \param uid is a fresh unique string to distinguish this variable * from other bound variables with the same name * \param type */ Expr vc_boundVarExpr(VC vc, char* name, char *uid, Type type); //! Create a FORALL quantifier. /*! Bvars is an array of bound variables of length numBvars. */ Type vc_forallExpr(VC vc, Expr* Bvars, int numBvars, Expr f); //! Set triggers for a forallExpr void vc_setTriggers(VC vc, Expr e, int numTrigs, Expr* triggers); //! Create an EXISTS quantifier. /*! Bvars is an array of bound variables of length numBvars. */ Expr vc_existsExpr(VC vc, Expr* Bvars, int numBvars, Expr f); //! Lambda-expression Op vc_lambdaExpr(VC vc, int numVars, Expr* vars, Expr body); ///////////////////////////////////////////////////////////////////////////// // Context-related methods // ///////////////////////////////////////////////////////////////////////////// //! Set the resource limit (0==unlimited, 1==exhausted). /*! Currently, the limit is the total number of processed facts. */ void vc_setResourceLimit(VC vc, unsigned limit); //! Assert a new formula in the current context. /*! The formula must have Boolean type. */ void vc_assertFormula(VC vc, Expr e); //! Register an atomic formula of interest. /*! Registered atoms are tracked by the decision procedures. If one of them is deduced to be true or false, it is added to a list of implied literals. Implied literals can be retrieved with the getImpliedLiteral function */ void vc_registerAtom(VC vc, Expr e); //! Return next literal implied by last assertion. Null if none. /*! Returned literals are either registered atomic formulas or their negation */ Expr vc_getImpliedLiteral(VC vc); //! Simplify e with respect to the current context Expr vc_simplify(VC vc, Expr e); //! Check validity of e in the current context. /*! Possible results are: 0 = invalid, 1 = valid, 2 = abort, 3 = unknown, * -100 = exception (type error, internal error, etc). * If the result is 1, then the resulting context is the same as * the starting context. If the result is 0 or 3, then the resulting * context is a context in which e is false (though the context may be * inconsistent in the case of an unknown result). e must have Boolean * type. In the case of a result of -100, refer to vc_get_error_string() * to see what went wrong. */ int vc_query(VC vc, Expr e); //! Get the next model /*! This method should only be called after a query which returns 0. Its return values are as for vc_query(). */ int vc_checkContinue(VC vc); //! Restart the most recent query with e as an additional assertion. /*! This method should only be called after a query which returns 0. Its return values are as for vc_query(). */ int vc_restart(VC vc, Expr e); //! Returns to context immediately before last invalid query. /*! This method should only be called after a query which returns 0. */ void vc_returnFromCheck(VC vc); //! Get assumptions made by the user in this and all previous contexts. /*! User assumptions are created either by calls to assertFormula or by a * call to query. In the latter case, the negated query is added as an * assumption. The caller is responsible for freeing the array when * finished with it. */ Expr* vc_getUserAssumptions(VC vc, int* size); //! Get assumptions made internally in this and all previous contexts. /*! Internal assumptions are literals assumed by the sat solver. * The caller is responsible for freeing the array when finished with it by * calling vc_deleteVector. */ Expr* vc_getInternalAssumptions(VC vc, int* size); //! Get all assumptions made in this and all previous contexts. /*! * The caller is responsible for freeing the array when finished with it by * calling vc_deleteVector. */ Expr* vc_getAssumptions(VC vc, int* size); //yeting, for proof translation, get the assumptions used. //the assumptions used are different from the user assumptions. //the assumptions used are preprocessed if 'preprocess' is ena Expr vc_getProofAssumptions(VC vc); //yeting, for proof translation, Expr vc_getProofQuery(VC vc); //! Returns the set of assumptions used in the proof of queried formula. /*! It returns a subset of getAssumptions(). If the last query was false * or there has not yet been a query, it does nothing. * The caller is responsible for freeing the array when finished with it by * calling vc_deleteVector. */ Expr* vc_getAssumptionsUsed(VC vc, int* size); //! Return the counterexample after a failed query. /*! This method should only be called after a query which returns * false. It will try to return the simplest possible set of * assertions which are sufficient to make the queried expression * false. The caller is responsible for freeing the array when finished with * it by calling vc_deleteVector. */ Expr* vc_getCounterExample(VC vc, int* size); //! Will assign concrete values to all user created variables /*! This function should only be called after a query which return false. * Returns an array of Exprs with size *size. * The caller is responsible for freeing the array when finished with it by * calling vc_deleteVector. */ Expr* vc_getConcreteModel(VC vc, int* size); // Returns true if the current context is inconsistent. /*! Also returns a minimal set of assertions used to determine the * inconsistency. The caller is responsible for freeing the array when finished * with it by calling vc_deleteVector. */ int vc_inconsistent(VC vc, Expr** assumptions, int* size); //! Returns non-NULL if the invalid result from last query() is imprecise /*! * The return value is filled with the reasons for incompleteness (it * is intended to be shown to the end user). The caller is responsible for * freeing the string returned by calling vc_deleteString. */ char* vc_incomplete(VC vc); //! Returns the proof for the last proven query Expr vc_getProof(VC vc); //! Returns the proof of a .cvc file, if it is valid. Expr vc_getProofOfFile(VC vc, char * filename); //! Returns the TCC of the last assumption or query /*! Returns Null Expr if no assumptions or queries were performed. */ Expr vc_getTCC(VC vc); //! Return the set of assumptions used in the proof of the last TCC /*! The caller is responsible for freeing the array when finished with it by * calling vc_deleteVector. */ Expr* vc_getAssumptionsTCC(VC vc, int* size); //! Returns the proof of TCC of the last assumption or query /*! Returns Null Expr if no assumptions or queries were performed. */ Expr vc_getProofTCC(VC vc); //! After successful query, return its closure |- Gamma => phi /*! Turn a valid query Gamma |- phi into an implication * |- Gamma => phi. * * Returns Null Expr if last query was invalid. */ Expr vc_getClosure(VC vc); //! Construct a proof of the query closure |- Gamma => phi /*! Returns Null if last query was Invalid. */ Expr vc_getProofClosure(VC vc); //! Returns the current stack level. Initial level is 0. int vc_stackLevel(VC vc); //! Checkpoint the current context and increase the scope level void vc_push(VC vc); //! Restore the current context to its state at the last checkpoint void vc_pop(VC vc); //! Restore the current context to the given stackLevel. /*! stackLevel must be less than or equal to the current stack level. */ void vc_popto(VC vc, int stackLevel); //! Get the current context Context* vc_getCurrentContext(VC vc); /* ---------------------------------------------------------------------- */ /* Util */ /* ---------------------------------------------------------------------- */ // Order //! Compares two expressions /*! If e1 < e2, e1==e2, and e1 > e2, it returns -1, 0, 1 * respectively. A return value of -100 signals an error (refer to * vc_get_error_string() for details). * * Can't be 'compare' because already defined in ocaml */ int vc_compare_exprs(Expr e1,Expr e2); // Printing //! Convert Expr to string char* vc_exprString(Expr e); //! Convert Type to string char* vc_typeString(Type t); // What kind of Expr? int vc_isClosure(Expr e); int vc_isQuantifier(Expr e); int vc_isLambda(Expr e); Expr vc_isVar(Expr e); int vc_arity(Expr e); int vc_getKind(Expr e); Expr vc_getChild(Expr e, int i); int vc_getNumVars(Expr e); Expr vc_getVar(Expr e, int i); Expr vc_getBody(Expr e); Expr vc_getExistential(Expr e); Expr vc_getFun(VC vc, Expr e); Expr vc_toExpr(Type t); //! Translate a kind int to a string const char* vc_getKindString(VC vc,int kind); //! Translate a kind string to an int int vc_getKindInt(VC vc,char* kind_name); //! Return an int from a rational expression int vc_getInt(Expr e); //! Return an int from a constant bitvector expression int vc_getBVInt(VC vc, Expr e); //! Return an unsigned int from a constant bitvector expression unsigned int vc_getBVUnsigned(VC vc, Expr e); // Debug int vc_get_error_status(); void vc_reset_error_status(); char* vc_get_error_string(); //! Print statistics void vc_print_statistics(VC vc); #endif