Index: tcc4tcl.tcl
==================================================================
--- tcc4tcl.tcl
+++ tcc4tcl.tcl
@@ -176,10 +176,20 @@
 		if {[llength $adefs_c] == 0} {
 			set adefs_c "void"
 		} else {
 			set adefs_c [join $adefs_c {, }]
 		}
+
+		# Determine actual C return type:
+		switch -- $rtype {
+			"ok" {
+				set rtype_c "int"
+			}
+			default {
+				set rtype_c $rtype
+			}
+		}
 
 		# Determine how to return in failure
 		if {$rtype != "void"} {
 			if {[info exists returnErrorValue]} {
 				set return_failure "return(${returnErrorValue})"
@@ -202,11 +212,11 @@
 		} else {
 			set return_failure "return"
 		}
 
 		# Define the C function
-		_ccode $handle "$rtype $cname\($adefs_c) \{"
+		_ccode $handle "$rtype_c $cname\($adefs_c) \{"
 
 		## Define the Tcl return value checking variable
 		_ccode $handle "    int tclrv;"
 
 		## If the interpreters return value is relevant, create a variable to store it
@@ -214,11 +224,11 @@
 			_ccode $handle "    Tcl_Obj *rv_interp;"
 		}
 
 		## If we are returning a value, declare a variable for that
 		if {$rtype != "void"} {
-			_ccode $handle "    $rtype rv;"
+			_ccode $handle "    $rtype_c rv;"
 		}
 
 		## If we need to create a new interpreter, do so
 		if {$newInterp} {
 			set interp_name "ip"
@@ -318,11 +328,11 @@
 		}
 
 		switch -- $rtype {
 			void { }
 			ok {
-				_ccode $handle "    rv = 0;"
+				_ccode $handle "    rv = TCL_OK;"
 			}
 			int {
 				_ccode $handle "    if (Tcl_GetIntFromObj(ip, rv_interp, &rv) != TCL_OK) $return_failure;"
 			}
 			long {

Index: test.tcl
==================================================================
--- test.tcl
+++ test.tcl
@@ -169,7 +169,13 @@
 $handle go
 puts [callToTcl1 3]
 
 set handle [tcc4tcl::new]
 $handle proc callToTclBinary {char* blob int blob_Length} ok {
-	puts "Blob: $blob"
+	puts "Blob: $blob ([string length $blob])"
+}
+$handle cproc callToTclBinaryWrapper {} void {
+	callToTclBinary("test\x00test", 9);
 }
+puts [$handle code]
+$handle go
+callToTclBinaryWrapper