diff --git a/tools/binpac/src/pac_action.cc b/tools/binpac/src/pac_action.cc
index 0b1ac3574f..ca9f72d96e 100644
--- a/tools/binpac/src/pac_action.cc
+++ b/tools/binpac/src/pac_action.cc
@@ -103,7 +103,7 @@ Type *ActionParam::DataType() const
 		if ( ! member_type )
 			{
 			throw Exception(type()->field_id(),
-				fmt("cannot find member type for `%s.%s'",
+				strfmt("cannot find member type for `%s.%s'",
 				    type()->type_id()->Name(),
 				    type()->field_id()->Name()));
 			}
diff --git a/tools/binpac/src/pac_array.cc b/tools/binpac/src/pac_array.cc
index 1f2bacc5d5..05eefdeb6c 100644
--- a/tools/binpac/src/pac_array.cc
+++ b/tools/binpac/src/pac_array.cc
@@ -205,9 +205,9 @@ void ArrayType::Prepare(Env *env, int flags)
 	{
 	if ( flags & TO_BE_PARSED )
 		{
-		ID *arraylength_var = new ID(fmt("%s__arraylength", value_var()->Name()));
-		ID *elem_var = new ID(fmt("%s__elem", value_var()->Name()));
-		ID *elem_it_var = new ID(fmt("%s__it", elem_var->Name()));
+		ID *arraylength_var = new ID(strfmt("%s__arraylength", value_var()->Name()));
+		ID *elem_var = new ID(strfmt("%s__elem", value_var()->Name()));
+		ID *elem_it_var = new ID(strfmt("%s__it", elem_var->Name()));
 
 		elem_var_field_ =
 			new ParseVarField(Field::CLASS_MEMBER, elem_var, elemtype_);
@@ -235,7 +235,7 @@ void ArrayType::Prepare(Env *env, int flags)
 
 			// Add elem_dataptr_var only when not parsing incrementally
 			ID *elem_dataptr_var =
-				new ID(fmt("%s__dataptr", elem_var->Name()));
+				new ID(strfmt("%s__dataptr", elem_var->Name()));
 			elem_dataptr_var_field_ = new TempVarField(
 				elem_dataptr_var,
 				extern_type_const_byteptr->Clone());
@@ -385,7 +385,7 @@ void ArrayType::GenCleanUpCode(Output *out_cc, Env *env)
 		{
 		if ( ! elem_var_field_ )
 			{
-			ID *elem_var = new ID(fmt("%s__elem", value_var()->Name()));
+			ID *elem_var = new ID(strfmt("%s__elem", value_var()->Name()));
 			elem_var_field_ =
 				new ParseVarField(
 					Field::NOT_CLASS_MEMBER,
@@ -623,7 +623,7 @@ void ArrayType::DoGenParseCode(Output *out_cc, Env *env,
 void ArrayType::GenUntilInputCheck(Output *out_cc, Env *env)
 	{
 	ID *elem_input_var_id = new ID(
-		fmt("%s__elem_input", value_var()->Name()));
+		strfmt("%s__elem_input", value_var()->Name()));
 	elem_input_var_field_ = new TempVarField(
 		elem_input_var_id, extern_type_const_bytestring->Clone());
 	elem_input_var_field_->Prepare(env);
diff --git a/tools/binpac/src/pac_case.cc b/tools/binpac/src/pac_case.cc
index 42ef5fd15f..1e501fc301 100644
--- a/tools/binpac/src/pac_case.cc
+++ b/tools/binpac/src/pac_case.cc
@@ -63,7 +63,7 @@ void CaseType::Prepare(Env* env, int flags)
 	{
 	ASSERT(flags & TO_BE_PARSED);
 
-	index_var_ = new ID(fmt("%s_case_index", value_var()->Name()));
+	index_var_ = new ID(strfmt("%s_case_index", value_var()->Name()));
 	env->AddID(index_var_, MEMBER_VAR, extern_type_int);
 
 	// Sort the cases_ to put the default case at the end of the list
diff --git a/tools/binpac/src/pac_conn.cc b/tools/binpac/src/pac_conn.cc
index d9159cae5a..5e2542e483 100644
--- a/tools/binpac/src/pac_conn.cc
+++ b/tools/binpac/src/pac_conn.cc
@@ -43,7 +43,7 @@ void ConnDecl::ProcessFlowElement(AnalyzerFlow *flow_elem)
 	if ( flows_[flow_index] )
 		{
 		throw Exception(flow_elem,
-		                fmt("%sflow already defined", 
+		                strfmt("%sflow already defined", 
 		                    flow_index == 0 ? "up" : "down"));
 		}
 
diff --git a/tools/binpac/src/pac_context.cc b/tools/binpac/src/pac_context.cc
index 94e4c4ce47..abf3c73a3c 100644
--- a/tools/binpac/src/pac_context.cc
+++ b/tools/binpac/src/pac_context.cc
@@ -39,7 +39,7 @@ namespace {
 AnalyzerContextDecl::AnalyzerContextDecl(
 		ID *id, 
 		ContextFieldList *context_fields)
-	: TypeDecl(new ID(fmt("Context%s", id->Name())), 
+	: TypeDecl(new ID(strfmt("Context%s", id->Name())), 
 		ContextFieldsToParams(context_fields), 
 		new DummyType())
 	{
@@ -47,7 +47,7 @@ AnalyzerContextDecl::AnalyzerContextDecl(
 	if ( current_analyzer_context_ != 0 )
 		{
 		throw Exception(this, 
-		                fmt("multiple declaration of analyzer context; "
+		                strfmt("multiple declaration of analyzer context; "
 		                    "the previous one is `%s'",
 		                    current_analyzer_context_->id()->Name()));
 		}
@@ -108,7 +108,7 @@ string AnalyzerContextDecl::mb_buffer(Env *env)
 	{
 	// A hack. The orthodox way would be to build an Expr of
 	// context.flow_buffer_var, and then EvalExpr.
-	return fmt("%s->%s()", 
+	return strfmt("%s->%s()", 
 		env->RValue(analyzer_context_id), 
 		kFlowBufferVar);
 	}
diff --git a/tools/binpac/src/pac_cstr.cc b/tools/binpac/src/pac_cstr.cc
index fb6db4b0b9..45e0b78f5e 100644
--- a/tools/binpac/src/pac_cstr.cc
+++ b/tools/binpac/src/pac_cstr.cc
@@ -49,7 +49,7 @@ int expand_escape(const char*& s)
 
 		int result;
 		if ( sscanf(start, "%3o", &result) != 1 )
-			throw EscapeException(fmt("bad octal escape: \"%s", start));
+			throw EscapeException(strfmt("bad octal escape: \"%s", start));
 
 		return result;
 		}
@@ -65,7 +65,7 @@ int expand_escape(const char*& s)
 
 		int result;
 		if ( sscanf(start, "%2x", &result) != 1 )
-			throw EscapeException(fmt("bad hexadecimal escape: \"%s", start));
+			throw EscapeException(strfmt("bad hexadecimal escape: \"%s", start));
 
 		return result;
 		}
diff --git a/tools/binpac/src/pac_decl.cc b/tools/binpac/src/pac_decl.cc
index 3c3ae95aa9..0bf371ce31 100644
--- a/tools/binpac/src/pac_decl.cc
+++ b/tools/binpac/src/pac_decl.cc
@@ -132,7 +132,7 @@ int HelperDecl::helper_id_seq = 0;
 HelperDecl::HelperDecl(HelperType helper_type, 
                        ID* context_id, 
                        EmbeddedCode* code)
- 	: Decl(new ID(fmt("helper_%d", ++helper_id_seq)), HELPER), 
+ 	: Decl(new ID(strfmt("helper_%d", ++helper_id_seq)), HELPER), 
 	  helper_type_(helper_type),
 	  context_id_(context_id),
 	  code_(code)
diff --git a/tools/binpac/src/pac_exception.cc b/tools/binpac/src/pac_exception.cc
index b614c2a6f6..e9648495fd 100644
--- a/tools/binpac/src/pac_exception.cc
+++ b/tools/binpac/src/pac_exception.cc
@@ -3,15 +3,16 @@
 #include "pac_id.h"
 #include "pac_utils.h"
 
-Exception::Exception(const Object* o, const char* msg)
+Exception::Exception(const Object* o, string msg)
 	{
 	if ( o )
 		{
 		msg_ = o->Location();
 		msg_ += ": error : ";
 		}
-	if ( msg )
-		msg_ += msg;
+
+	msg_ += msg;
+
 	if ( FLAGS_pac_debug ) 
 		{
 		DEBUG_MSG("Exception: %s\n", msg_.c_str());
@@ -22,49 +23,49 @@ Exception::Exception(const Object* o, const char* msg)
 ExceptionIDNotFound::ExceptionIDNotFound(const ID* id)
 	: Exception(id), id_(id) 
 	{
-	append(fmt("`%s' undeclared", id_->Name()));
+	append(strfmt("`%s' undeclared", id_->Name()));
 	}
 
 ExceptionIDRedefinition::ExceptionIDRedefinition(const ID* id)
 	: Exception(id), id_(id) 
 	{
-	append(fmt("`%s' redefined", id_->Name()));
+	append(strfmt("`%s' redefined", id_->Name()));
 	}
 
 ExceptionIDNotEvaluated::ExceptionIDNotEvaluated(const ID* id)
 	: Exception(id), id_(id) 
 	{
-	append(fmt("ID `%s' not evaluated before used", id->Name()));
+	append(strfmt("ID `%s' not evaluated before used", id->Name()));
 	}
 
 ExceptionIDNotField::ExceptionIDNotField(const ID* id)
 	: Exception(id), id_(id) 
 	{
-	append(fmt("ID `%s' is not a field", id_->Name()));
+	append(strfmt("ID `%s' is not a field", id_->Name()));
 	}
 
 ExceptionMemberNotFound::ExceptionMemberNotFound(const ID* type_id, 
                                                  const ID *member_id)
 	: Exception(member_id), type_id_(type_id), member_id_(member_id)
 	{
-	append(fmt("type %s does not have member `%s'",
+	append(strfmt("type %s does not have member `%s'",
 	           type_id_->Name(), member_id_->Name()));
 	}
 
 ExceptionCyclicDependence::ExceptionCyclicDependence(const ID* id)
 	: Exception(id), id_(id) 
 	{
-	append(fmt("cyclic dependence through `%s'", id_->Name()));
+	append(strfmt("cyclic dependence through `%s'", id_->Name()));
 	}
 
-ExceptionPaddingError::ExceptionPaddingError(const Object* o, const char* msg)
+ExceptionPaddingError::ExceptionPaddingError(const Object* o, string msg)
 	: Exception(o)
 	{
-	append(msg);
+	append(msg.c_str());
 	}
 
 ExceptionNonConstExpr::ExceptionNonConstExpr(const Expr* expr)
 	: Exception(expr), expr(expr)
 	{
-	append(fmt("Expression `%s' is not constant", expr->orig()));
+	append(strfmt("Expression `%s' is not constant", expr->orig()));
 	}
diff --git a/tools/binpac/src/pac_exception.h b/tools/binpac/src/pac_exception.h
index 5508e75537..5920af0d54 100644
--- a/tools/binpac/src/pac_exception.h
+++ b/tools/binpac/src/pac_exception.h
@@ -9,10 +9,10 @@ using namespace std;
 class Exception
 {
 public:
-	Exception(const Object* o, const char* msg = 0);
+	Exception(const Object* o, string msg = "");
 
 	const char* msg() const 	{ return msg_.c_str(); }
-	void append(const char* s) 	{ msg_ += s; }
+	void append(string s) 	{ msg_ += s; }
 
 private:
 	string msg_;
@@ -61,7 +61,7 @@ private:
 class ExceptionPaddingError : public Exception
 {
 public:
-	ExceptionPaddingError(const Object* o, const char* msg);
+	ExceptionPaddingError(const Object* o, string msg);
 };
 
 class ExceptionIDNotField : public Exception
diff --git a/tools/binpac/src/pac_expr.cc b/tools/binpac/src/pac_expr.cc
index df499f7cef..3f74aa8e3f 100644
--- a/tools/binpac/src/pac_expr.cc
+++ b/tools/binpac/src/pac_expr.cc
@@ -72,7 +72,7 @@ Expr::Expr(ID* arg_id)
 	expr_type_ = EXPR_ID;
 	id_ = arg_id;
 	num_operands_ = 0;
-	orig_ = fmt("%s", id_->Name());
+	orig_ = strfmt("%s", id_->Name());
 	}
 
 Expr::Expr(Number* arg_num)
@@ -82,7 +82,7 @@ Expr::Expr(Number* arg_num)
 	expr_type_ = EXPR_NUM;
 	num_ = arg_num;
 	num_operands_ = 0;
-	orig_ = fmt("((int) %s)", num_->Str());
+	orig_ = strfmt("((int) %s)", num_->Str());
 	}
 
 Expr::Expr(ConstString *cstr)
@@ -102,7 +102,7 @@ Expr::Expr(RegEx *regex)
 	expr_type_ = EXPR_REGEX;
 	regex_ = regex;
 	num_operands_ = 0;
-	orig_ = fmt("/%s/", regex_->str().c_str());
+	orig_ = strfmt("/%s/", regex_->str().c_str());
 	}
 
 Expr::Expr(ExprType arg_type, Expr* op1)
@@ -112,7 +112,7 @@ Expr::Expr(ExprType arg_type, Expr* op1)
 	expr_type_ = arg_type;
 	num_operands_ = 1;
 	operand_[0] = op1;
-	orig_ = fmt(expr_fmt[expr_type_], op1->orig());
+	orig_ = strfmt(expr_fmt[expr_type_], op1->orig());
 	}
 
 Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2)
@@ -124,7 +124,7 @@ Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2)
 	operand_[0] = op1;
 	operand_[1] = op2;
 	operand_[2] = 0;
-	orig_ = fmt(expr_fmt[expr_type_], op1->orig(), op2->orig());
+	orig_ = strfmt(expr_fmt[expr_type_], op1->orig(), op2->orig());
 	}
 
 Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2, Expr* op3)
@@ -136,7 +136,7 @@ Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2, Expr* op3)
 	operand_[0] = op1;
 	operand_[1] = op2;
 	operand_[2] = op3;
-	orig_ = fmt(expr_fmt[expr_type_], op1->orig(), op2->orig(), op3->orig());
+	orig_ = strfmt(expr_fmt[expr_type_], op1->orig(), op2->orig(), op3->orig());
 	}
 
 Expr::Expr(ExprList *args)
@@ -196,16 +196,16 @@ void Expr::GenStrFromFormat(Env *env)
 	switch ( num_operands_ )
 		{
 		case 1:
-			str_ = fmt(expr_fmt[expr_type_], 
+			str_ = strfmt(expr_fmt[expr_type_], 
 				operand_[0]->str());
 			break; 
 		case 2:
-			str_ = fmt(expr_fmt[expr_type_], 
+			str_ = strfmt(expr_fmt[expr_type_], 
 				operand_[0]->str(),
 				operand_[1]->str());
 			break; 
 		case 3:
-			str_ = fmt(expr_fmt[expr_type_], 
+			str_ = strfmt(expr_fmt[expr_type_], 
 				operand_[0]->str(),
 				operand_[1]->str(),
 				operand_[2]->str());
@@ -334,11 +334,19 @@ void Expr::GenEval(Output* out_cc, Env* env)
 
 			Type *ty0 = operand_[0]->DataType(env);
 
-			str_ = fmt("%s%s",
-				operand_[0]->EvalExpr(out_cc, env),
-				ty0 ? 
-				ty0->EvalMember(operand_[1]->id()).c_str() :
-				fmt("->%s()", operand_[1]->id()->Name()));
+			if ( ty0 )
+				{
+				str_ = strfmt("%s%s",
+				              operand_[0]->EvalExpr(out_cc, env),
+				              ty0->EvalMember(operand_[1]->id()).c_str());
+				}
+			else
+				{
+				string tmp = strfmt("->%s()", operand_[1]->id()->Name());
+				str_ = strfmt("%s%s",
+				              operand_[0]->EvalExpr(out_cc, env),
+				              tmp.c_str());
+				}
 			}
 			break;
 
@@ -354,7 +362,7 @@ void Expr::GenEval(Output* out_cc, Env* env)
 			if ( ty0 )
 				str_ = ty0->EvalElement(v0, v1);
 			else
-				str_ = fmt("%s[%s]", v0.c_str(), v1.c_str());
+				str_ = strfmt("%s[%s]", v0.c_str(), v1.c_str());
 			}
 			break;
 
@@ -368,7 +376,7 @@ void Expr::GenEval(Output* out_cc, Env* env)
 				{
 				if ( (rf = GetRecordField(id, env)) != 0 )
 					{
-					str_ = fmt("%s", rf->FieldSize(out_cc, env));
+					str_ = strfmt("%s", rf->FieldSize(out_cc, env));
 					}
 				}
 			catch ( ExceptionIDNotFound &e )
@@ -377,7 +385,7 @@ void Expr::GenEval(Output* out_cc, Env* env)
 					{
 					int ty_size = ty->StaticSize(global_env());
 					if ( ty_size >= 0 )
-						str_ = fmt("%d", ty_size);
+						str_ = strfmt("%d", ty_size);
 					else
 						throw Exception(id, "unknown size");
 					}
@@ -391,7 +399,7 @@ void Expr::GenEval(Output* out_cc, Env* env)
 			{
 			const ID *id = operand_[0]->id();
 			RecordField *rf = GetRecordField(id, env);
-			str_ = fmt("%s", rf->FieldOffset(out_cc, env));
+			str_ = strfmt("%s", rf->FieldOffset(out_cc, env));
 			}
 			break;
 
@@ -501,7 +509,7 @@ Type *Expr::DataType(Env *env) const
 			if ( ! Type::CompatibleTypes(type1, type2) )
 				{
 				throw Exception(this, 
-					fmt("type mismatch: %s vs %s",
+					strfmt("type mismatch: %s vs %s",
 					    type1->DataTypeStr().c_str(),
 					    type2->DataTypeStr().c_str()));
 				}
@@ -526,7 +534,7 @@ Type *Expr::DataType(Env *env) const
 					if ( ! Type::CompatibleTypes(type1, type2) )
 						{
 						throw Exception(this, 
-							fmt("type mismatch: %s vs %s",
+							strfmt("type mismatch: %s vs %s",
 					    		    type1->DataTypeStr().c_str(),
 					                    type2->DataTypeStr().c_str()));
 						}
@@ -581,7 +589,7 @@ string Expr::DataTypeStr(Env *env) const
 	if ( ! type )
 		{
 		throw Exception(this, 
-		                fmt("cannot find data type for expression `%s'",
+		                strfmt("cannot find data type for expression `%s'",
 		                    orig()));
 		}
 
@@ -605,7 +613,7 @@ string Expr::SetFunc(Output *out, Env *env)
 			break;
 		default:
 			throw Exception(this, 
-			                fmt("cannot generate set function "
+			                strfmt("cannot generate set function "
 			                    "for expression `%s'", orig()));
 			break;
 		}
diff --git a/tools/binpac/src/pac_id.cc b/tools/binpac/src/pac_id.cc
index b8431e6f0a..447348e978 100644
--- a/tools/binpac/src/pac_id.cc
+++ b/tools/binpac/src/pac_id.cc
@@ -39,7 +39,7 @@ int ID::anonymous_id_seq = 0;
 
 ID *ID::NewAnonymousID(const string &prefix)
 	{
-	ID *id = new ID(fmt("%s%03d", prefix.c_str(), ++anonymous_id_seq));
+	ID *id = new ID(strfmt("%s%03d", prefix.c_str(), ++anonymous_id_seq));
 	id->anonymous_id_ = true;
 	return id;
 	}
@@ -297,7 +297,7 @@ void Env::SetEvaluated(const ID* id, bool v)
 			{
 			throw Exception(
 				context_object_,
-				fmt("INTERNAL ERROR: "
+				strfmt("INTERNAL ERROR: "
 				"evaluating let field '%s' in a branch! "
 				"To work around this problem, "
 				"add '&requires(%s)' to the case type. "
diff --git a/tools/binpac/src/pac_id.h b/tools/binpac/src/pac_id.h
index 6ac89687d4..06ffeb9f63 100644
--- a/tools/binpac/src/pac_id.h
+++ b/tools/binpac/src/pac_id.h
@@ -43,7 +43,7 @@ class Evaluatable;
 class ID : public Object
 {
 public:
-	ID(const char *arg_name)
+	ID(string arg_name)
 		: name(arg_name), anonymous_id_(false)
 		{
 		locname = nfmt("%s:%s", Location(), Name());
diff --git a/tools/binpac/src/pac_let.cc b/tools/binpac/src/pac_let.cc
index fba5f1cfc8..c850784554 100644
--- a/tools/binpac/src/pac_let.cc
+++ b/tools/binpac/src/pac_let.cc
@@ -156,8 +156,9 @@ void LetDecl::GenCode(Output * out_h, Output *out_cc)
 void LetDecl::GenEval(Output *out_cc, Env * /* env */)
 	{
 	Env *env = global_env();
+	string tmp = strfmt("%s const", type_->DataTypeStr().c_str());
 	out_cc->println("%s %s = %s;", 
-		fmt("%s const", type_->DataTypeStr().c_str()),
+		tmp.c_str(),
 		env->LValue(id_), 
 	       	expr_->EvalExpr(out_cc, env));
 
diff --git a/tools/binpac/src/pac_main.cc b/tools/binpac/src/pac_main.cc
index adb8d0eb51..0dbb43342e 100644
--- a/tools/binpac/src/pac_main.cc
+++ b/tools/binpac/src/pac_main.cc
@@ -103,7 +103,8 @@ int compile(const char* filename)
 	FILE* fp_input = fopen(filename, "r");
 	if ( ! fp_input )
 		{
-		perror(fmt("Error in opening %s", filename));
+		string tmp = strfmt("Error in opening %s", filename);
+		perror(tmp.c_str());
 		return -1;
 		}
 	input_filename = filename;
@@ -142,8 +143,8 @@ int compile(const char* filename)
 		if ( yyparse() )
 			return 1;
 
-		Output out_h(fmt("%s.h", basename.c_str()));
-		Output out_cc(fmt("%s.cc", basename.c_str()));
+		Output out_h(strfmt("%s.h", basename.c_str()));
+		Output out_cc(strfmt("%s.cc", basename.c_str()));
 
 		header_output = &out_h;
 		source_output = &out_cc;
diff --git a/tools/binpac/src/pac_number.h b/tools/binpac/src/pac_number.h
index f923068700..f74b206417 100644
--- a/tools/binpac/src/pac_number.h
+++ b/tools/binpac/src/pac_number.h
@@ -7,7 +7,7 @@ class Number : public Object
 {
 public:
 	Number(int arg_n)
-		: s(fmt("%d", arg_n)), n(arg_n) {}
+		: s(strfmt("%d", arg_n)), n(arg_n) {}
 	Number(const char* arg_s, int arg_n)
 		: s(arg_s), n(arg_n) {}
 	const char* Str() const 	{ return s.c_str(); }
diff --git a/tools/binpac/src/pac_output.cc b/tools/binpac/src/pac_output.cc
index 32875bdee6..aec1e92dfc 100644
--- a/tools/binpac/src/pac_output.cc
+++ b/tools/binpac/src/pac_output.cc
@@ -15,9 +15,9 @@ OutputException::~OutputException()
 	{
 	}
 
-Output::Output(const char* filename)
+Output::Output(string filename)
 	{
-	fp = fopen(filename, "w");
+	fp = fopen(filename.c_str(), "w");
 	if ( ! fp )
 		throw OutputException(strerror(errno));
 	indent_ = 0;
diff --git a/tools/binpac/src/pac_output.h b/tools/binpac/src/pac_output.h
index b9d99a7dc5..26cfd72667 100644
--- a/tools/binpac/src/pac_output.h
+++ b/tools/binpac/src/pac_output.h
@@ -19,7 +19,7 @@ protected:
 
 class Output {
 public:
-	Output(const char *filename);
+	Output(string filename);
 	~Output();
 
 	int println(const char* fmt, ...);
diff --git a/tools/binpac/src/pac_record.cc b/tools/binpac/src/pac_record.cc
index 41a717653d..813f201b8b 100644
--- a/tools/binpac/src/pac_record.cc
+++ b/tools/binpac/src/pac_record.cc
@@ -328,7 +328,7 @@ const DataPtr& RecordField::getFieldEnd(Output* out_cc, Env* env)
 			{
 			// If not, we add a variable for the offset after the field
 			end_of_field_dataptr_var = new ID(
-				fmt("dataptr_after_%s", id()->Name()));
+				strfmt("dataptr_after_%s", id()->Name()));
 			env->AddID(end_of_field_dataptr_var, 
 		           	TEMP_VAR, 
 		           	extern_type_const_byteptr);
@@ -546,7 +546,7 @@ void RecordPaddingField::Prepare(Env* env)
 		{
 		if ( ! expr_->ConstFold(env, &wordsize_) )
 			throw ExceptionPaddingError(this, 
-				fmt("padding word size not a constant"));
+				strfmt("padding word size not a constant"));
 		}
 	}
 
@@ -585,7 +585,7 @@ int RecordPaddingField::StaticSize(Env* env, int offset) const
 			if ( offset > target_offset )
 				throw ExceptionPaddingError(
 					this,
-					fmt("current offset = %d, "
+					strfmt("current offset = %d, "
 					    "target offset = %d", 
 					    offset, target_offset));
 			return target_offset - offset;
diff --git a/tools/binpac/src/pac_redef.cc b/tools/binpac/src/pac_redef.cc
index 9f09b457bd..260a9ce621 100644
--- a/tools/binpac/src/pac_redef.cc
+++ b/tools/binpac/src/pac_redef.cc
@@ -16,7 +16,7 @@ Decl *find_decl(const ID *id)
 	if ( ! decl )
 		{
 		throw Exception(id, 
-		                fmt("cannot find declaration for %s", 
+		                strfmt("cannot find declaration for %s", 
 		                    id->Name()));
 		}
 
@@ -32,7 +32,7 @@ Decl *ProcessTypeRedef(const ID *id, FieldList *fieldlist)
 	if ( decl->decl_type() != Decl::TYPE )
 		{
 		throw Exception(id, 
-		                fmt("not a type declaration: %s", 
+		                strfmt("not a type declaration: %s", 
 		                    id->Name()));
 		}
 
@@ -74,7 +74,7 @@ Decl *ProcessCaseTypeRedef(const ID *id, CaseFieldList *casefieldlist)
 	if ( decl->decl_type() != Decl::TYPE )
 		{
 		throw Exception(id, 
-		                fmt("not a type declaration: %s", 
+		                strfmt("not a type declaration: %s", 
 		                    id->Name()));
 		}
 
@@ -85,7 +85,7 @@ Decl *ProcessCaseTypeRedef(const ID *id, CaseFieldList *casefieldlist)
 	if ( type->tot() != Type::CASE )
 		{
 		throw Exception(id, 
-		                fmt("not a case type: %s", 
+		                strfmt("not a case type: %s", 
 		                    id->Name()));
 		}
 
@@ -108,7 +108,7 @@ Decl *ProcessCaseExprRedef(const ID *id, CaseExprList *caseexprlist)
 	if ( decl->decl_type() != Decl::FUNC )
 		{
 		throw Exception(id, 
-		                fmt("not a function declaration: %s", 
+		                strfmt("not a function declaration: %s", 
 		                    id->Name()));
 		}
 
@@ -119,7 +119,7 @@ Decl *ProcessCaseExprRedef(const ID *id, CaseExprList *caseexprlist)
 	if ( ! expr ||expr->expr_type() != Expr::EXPR_CASE )
 		{
 		throw Exception(id, 
-		                fmt("function not defined by a case expression: %s", 
+		                strfmt("function not defined by a case expression: %s", 
 		                    id->Name()));
 		}
 
@@ -141,7 +141,7 @@ Decl *ProcessAnalyzerRedef(const ID *id,
 	if ( decl->decl_type() != decl_type )
 		{
 		throw Exception(id, 
-		                fmt("not a connection/flow declaration: %s", 
+		                strfmt("not a connection/flow declaration: %s", 
 		                    id->Name()));
 		}
 
@@ -160,7 +160,7 @@ Decl *ProcessTypeAttrRedef(const ID *id, AttrList *attrlist)
 	if ( decl->decl_type() != Decl::TYPE )
 		{
 		throw Exception(id, 
-		                fmt("not a type declaration: %s", 
+		                strfmt("not a type declaration: %s", 
 		                    id->Name()));
 		}
 
diff --git a/tools/binpac/src/pac_strtype.cc b/tools/binpac/src/pac_strtype.cc
index 2a80c005d7..1dc7832c5a 100644
--- a/tools/binpac/src/pac_strtype.cc
+++ b/tools/binpac/src/pac_strtype.cc
@@ -149,7 +149,7 @@ void StringType::Prepare(Env* env, int flags)
 	{
 	if ( (flags & TO_BE_PARSED) && StaticSize(env) < 0 )
 		{
-		ID *string_length_var = new ID(fmt("%s_string_length", 
+		ID *string_length_var = new ID(strfmt("%s_string_length", 
 			value_var() ? value_var()->Name() : "val"));
 		string_length_var_field_ = new TempVarField(
 			string_length_var, extern_type_int->Clone());
@@ -314,14 +314,16 @@ void StringType::DoGenParseCode(Output* out_cc, Env* env,
 	}
 
 void StringType::GenStringMismatch(Output* out_cc, Env* env, 
-		const DataPtr& data, const char *pattern)
+		const DataPtr& data, string pattern)
 	{
+	string tmp = 
+		strfmt("string((const char *) (%s), (const char *) %s).c_str()", 
+			data.ptr_expr(),
+			env->RValue(end_of_data));
 	out_cc->println("throw binpac::ExceptionStringMismatch(\"%s\", %s, %s);",
 		Location(), 
-		pattern,
-		fmt("string((const char *) (%s), (const char *) %s).c_str()", 
-			data.ptr_expr(),
-			env->RValue(end_of_data)));
+		pattern.c_str(),
+		tmp.c_str());
 	}
 
 void StringType::GenCheckingCStr(Output* out_cc, Env* env, 
@@ -341,7 +343,7 @@ void StringType::GenCheckingCStr(Output* out_cc, Env* env,
 		str_size.c_str());
 	out_cc->inc_indent();
 	out_cc->println("{");
-	GenStringMismatch(out_cc, env, data, str_val.c_str());
+	GenStringMismatch(out_cc, env, data, str_val);
 	out_cc->println("}");
 	out_cc->dec_indent();
 	}
@@ -378,8 +380,8 @@ void StringType::GenDynamicSizeRegEx(Output* out_cc, Env* env,
 		env->RValue(string_length_var()));
 	out_cc->inc_indent();
 	out_cc->println("{");
-	GenStringMismatch(out_cc, env, data, 
-		fmt("\"%s\"", regex_->str().c_str()));
+	string tmp = strfmt("\"%s\"", regex_->str().c_str());
+	GenStringMismatch(out_cc, env, data, tmp);
 	out_cc->println("}");
 	out_cc->dec_indent();
 	}
diff --git a/tools/binpac/src/pac_strtype.h b/tools/binpac/src/pac_strtype.h
index 55b35e54ab..81520d7b7c 100644
--- a/tools/binpac/src/pac_strtype.h
+++ b/tools/binpac/src/pac_strtype.h
@@ -44,7 +44,7 @@ protected:
 
 	// Generate a string mismatch exception
 	void GenStringMismatch(Output* out_cc, Env* env, 
-		const DataPtr& data, const char *pattern);
+		const DataPtr& data, string pattern);
 
 	void DoGenParseCode(Output* out, Env* env, const DataPtr& data, int flags);
 
diff --git a/tools/binpac/src/pac_type.cc b/tools/binpac/src/pac_type.cc
index 044a5305d1..aa338aa285 100644
--- a/tools/binpac/src/pac_type.cc
+++ b/tools/binpac/src/pac_type.cc
@@ -283,7 +283,7 @@ void Type::Prepare(Env* env, int flags)
 	if ( attr_if_expr() )
 		{
 		ASSERT(value_var());
-		ID *has_value_id = new ID(fmt("has_%s", value_var()->Name()));
+		ID *has_value_id = new ID(strfmt("has_%s", value_var()->Name()));
 		has_value_field_ = new LetField(has_value_id, 
 			extern_type_bool->Clone(),
 			attr_if_expr());
@@ -294,7 +294,7 @@ void Type::Prepare(Env* env, int flags)
 		{
 		ASSERT(flags & TO_BE_PARSED);
 		ID *parsing_complete_var = 
-			new ID(fmt("%s_parsing_complete", 
+			new ID(strfmt("%s_parsing_complete", 
 				value_var() ? value_var()->Name() : "val"));
 		DEBUG_MSG("Adding parsing complete var: %s\n",
 			parsing_complete_var->Name());
@@ -837,7 +837,7 @@ bool Type::AddSizeVar(Output* out_cc, Env* env)
 
 	ASSERT(! incremental_input());
 
-	ID *size_var_id = new ID(fmt("%s__size", 
+	ID *size_var_id = new ID(strfmt("%s__size", 
 		value_var() ? value_var()->Name() : decl_id()->Name()));
 
 	DEBUG_MSG("adding size var `%s' to env %p\n", size_var_id->Name(), env);
diff --git a/tools/binpac/src/pac_typedecl.cc b/tools/binpac/src/pac_typedecl.cc
index 35d52a098e..a26b2f7ab6 100644
--- a/tools/binpac/src/pac_typedecl.cc
+++ b/tools/binpac/src/pac_typedecl.cc
@@ -253,7 +253,7 @@ string TypeDecl::ParseFuncPrototype(Env* env)
 	if ( RequiresAnalyzerContext::compute(type_) )
 		{
 		Type *param_type = analyzer_context()->param_type();
-		params += fmt(", %s %s", 
+		params += strfmt(", %s %s", 
 			param_type->DataTypeConstRefStr().c_str(),
 			env->LValue(analyzer_context_id));
 		}
@@ -261,7 +261,7 @@ string TypeDecl::ParseFuncPrototype(Env* env)
 	// Add parameter "byteorder"
 	if ( type_->RequiresByteOrder() && ! type_->attr_byteorder_expr() )
 		{
-		params += fmt(", int %s", env->LValue(byteorder_id));
+		params += strfmt(", int %s", env->LValue(byteorder_id));
 		}
 
 	// Returns "<return type> %s<func name>(<params>)%s".
@@ -358,7 +358,8 @@ void TypeDecl::GenParseFunc(Output* out_h, Output* out_cc)
 
 	out_h->println(proto.c_str(), "", ";");
 
-	out_cc->println(proto.c_str(), fmt("%s::", class_name().c_str()), "");
+	string tmp = strfmt("%s::", class_name().c_str());
+	out_cc->println(proto.c_str(), tmp.c_str(), "");
 	out_cc->inc_indent();
 	out_cc->println("{");
 
@@ -382,7 +383,7 @@ void TypeDecl::GenInitialBufferLengthFunc(Output* out_h, Output* out_cc)
 	if ( init_buffer_length < 0 )  // cannot be statically determined
 		{
 		throw Exception(type()->attr_length_expr(), 
-		                fmt("cannot determine initial buffer length"
+		                strfmt("cannot determine initial buffer length"
 		                    " for type %s", id_->Name()));
 		}
 
diff --git a/tools/binpac/src/pac_utils.h b/tools/binpac/src/pac_utils.h
index 37898e4070..ec70e6be8b 100644
--- a/tools/binpac/src/pac_utils.h
+++ b/tools/binpac/src/pac_utils.h
@@ -9,7 +9,4 @@ char* copy_string(const char* s);
 string strfmt(const char* fmt, ...);
 char* nfmt(const char* fmt, ...);
 
-// const char* fmt(const char* fmt, ...);
-#define fmt(x...) strfmt(x).c_str()
-
 #endif /* pac_utils_h */