diff --git a/NAMESPACE b/NAMESPACE
index cfaba60ed..dcc5281ae 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -48,6 +48,7 @@ export("opt<-")
 export(.advance)
 export(.context)
 export(.dispatcher)
+export(.interrupt)
 export(.keep)
 export(.mark)
 export(.online)
diff --git a/R/sync.R b/R/sync.R
index 5c4097d45..559a49016 100644
--- a/R/sync.R
+++ b/R/sync.R
@@ -307,7 +307,8 @@ unlock <- function(socket) invisible(.Call(rnng_socket_unlock, socket))
 #' Dispatcher Socket
 #'
 #' Creates a Dispatcher socket, which is a special type of \sQuote{req} socket,
-#' with FIFO scheduling using a threaded implementation (for internal use only).
+#' with FIFO scheduling using a threaded implementation. Internal package
+#' function.
 #'
 #' @param host \sQuote{inproc://} url connecting the host to the thread.
 #' @param url the URLs at which to listen for rep nodes.
@@ -323,8 +324,8 @@ unlock <- function(socket) invisible(.Call(rnng_socket_unlock, socket))
 
 #' Read Online Status
 #'
-#' Reads the online status of threaded dispatcher sockets (for internal use
-#' only).
+#' Reads the online status of threaded dispatcher sockets. Internal package
+#' function.
 #'
 #' @param sock a dispatcher Socket.
 #'
@@ -334,3 +335,19 @@ unlock <- function(socket) invisible(.Call(rnng_socket_unlock, socket))
 #' @export
 #'
 .online <- function(sock) .Call(rnng_read_online, sock)
+
+#' Interrupt Switch
+#'
+#' Toggles on or off whether async receive completions trigger an interrupt.
+#' Internal package function.
+#'
+#' @return NULL.
+#'
+#' @examples
+#' .interrupt()
+#' .interrupt()
+#'
+#' @keywords internal
+#' @export
+#'
+.interrupt <- function() .Call(rnng_interrupt_switch)
diff --git a/R/utils.R b/R/utils.R
index 04e432b91..bd53db976 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -316,20 +316,18 @@ serial_config <- function(class, sfunc, ufunc, vec = FALSE)
 
 #' Set Serialization Marker
 #'
-#' Internal package function.
-#'
-#' @param x logical value.
+#' Toggles the serialization marker on or off. Internal package function.
 #'
-#' @return The logical value 'x' supplied.
+#' @return NULL.
 #'
 #' @examples
 #' .mark()
-#' .mark(FALSE)
+#' .mark()
 #'
 #' @keywords internal
 #' @export
 #'
-.mark <- function(x = TRUE) .Call(rnng_set_marker, x)
+.mark <- function() .Call(rnng_set_marker)
 
 #' Advances the RNG State
 #'
diff --git a/man/dot-dispatcher.Rd b/man/dot-dispatcher.Rd
index d08578b29..1d1da73fe 100644
--- a/man/dot-dispatcher.Rd
+++ b/man/dot-dispatcher.Rd
@@ -19,6 +19,7 @@ A \sQuote{req} Socket. The thread is attached as an attribute.
 }
 \description{
 Creates a Dispatcher socket, which is a special type of \sQuote{req} socket,
-with FIFO scheduling using a threaded implementation (for internal use only).
+with FIFO scheduling using a threaded implementation. Internal package
+function.
 }
 \keyword{internal}
diff --git a/man/dot-interrupt.Rd b/man/dot-interrupt.Rd
new file mode 100644
index 000000000..8b8dc120c
--- /dev/null
+++ b/man/dot-interrupt.Rd
@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/sync.R
+\name{.interrupt}
+\alias{.interrupt}
+\title{Interrupt Switch}
+\usage{
+.interrupt()
+}
+\value{
+NULL.
+}
+\description{
+Toggles on or off whether async receive completions trigger an interrupt.
+Internal package function.
+}
+\examples{
+.interrupt()
+.interrupt()
+
+}
+\keyword{internal}
diff --git a/man/dot-mark.Rd b/man/dot-mark.Rd
index 28392a614..f02e94b45 100644
--- a/man/dot-mark.Rd
+++ b/man/dot-mark.Rd
@@ -4,20 +4,17 @@
 \alias{.mark}
 \title{Set Serialization Marker}
 \usage{
-.mark(x = TRUE)
-}
-\arguments{
-\item{x}{logical value.}
+.mark()
 }
 \value{
-The logical value 'x' supplied.
+NULL.
 }
 \description{
-Internal package function.
+Toggles the serialization marker on or off. Internal package function.
 }
 \examples{
 .mark()
-.mark(FALSE)
+.mark()
 
 }
 \keyword{internal}
diff --git a/man/dot-online.Rd b/man/dot-online.Rd
index 0b1239516..17970ca38 100644
--- a/man/dot-online.Rd
+++ b/man/dot-online.Rd
@@ -13,7 +13,7 @@
 An vector of integer values.
 }
 \description{
-Reads the online status of threaded dispatcher sockets (for internal use
-only).
+Reads the online status of threaded dispatcher sockets. Internal package
+function.
 }
 \keyword{internal}
diff --git a/src/aio.c b/src/aio.c
index 48f260f11..7a6fe1f1e 100644
--- a/src/aio.c
+++ b/src/aio.c
@@ -16,6 +16,7 @@
 
 // nanonext - C level - Async Functions ----------------------------------------
 
+#define NANONEXT_SIGNALS
 #include "nanonext.h"
 
 // internals -------------------------------------------------------------------
@@ -65,6 +66,14 @@ static void raio_complete(void *arg) {
   if (raio->cb != NULL)
     later2(raio_invoke_cb, raio->cb);
 
+  if (nano_interrupt) {
+#ifdef _WIN32
+    raise(SIGINT);
+#else
+    kill(getpid(), SIGINT);
+#endif
+  }
+
 }
 
 static void iraio_complete(void *arg) {
diff --git a/src/init.c b/src/init.c
index f8818d12d..d9d25acbe 100644
--- a/src/init.c
+++ b/src/init.c
@@ -20,6 +20,7 @@
 
 void (*eln2)(void (*)(void *), void *, double, int) = NULL;
 
+int nano_interrupt = 0;
 uint8_t special_bit = 0;
 
 nng_mtx *nano_wait_mtx;
@@ -153,6 +154,7 @@ static const R_CallMethodDef callMethods[] = {
   {"rnng_eval_safe", (DL_FUNC) &rnng_eval_safe, 1},
   {"rnng_fini", (DL_FUNC) &rnng_fini, 0},
   {"rnng_get_opt", (DL_FUNC) &rnng_get_opt, 2},
+  {"rnng_interrupt_switch", (DL_FUNC) &rnng_interrupt_switch, 0},
   {"rnng_is_error_value", (DL_FUNC) &rnng_is_error_value, 1},
   {"rnng_is_nul_byte", (DL_FUNC) &rnng_is_nul_byte, 1},
   {"rnng_listen", (DL_FUNC) &rnng_listen, 5},
@@ -176,7 +178,7 @@ static const R_CallMethodDef callMethods[] = {
   {"rnng_send", (DL_FUNC) &rnng_send, 4},
   {"rnng_send_aio", (DL_FUNC) &rnng_send_aio, 5},
   {"rnng_serial_config", (DL_FUNC) &rnng_serial_config, 4},
-  {"rnng_set_marker", (DL_FUNC) &rnng_set_marker, 1},
+  {"rnng_set_marker", (DL_FUNC) &rnng_set_marker, 0},
   {"rnng_set_opt", (DL_FUNC) &rnng_set_opt, 3},
   {"rnng_set_promise_context", (DL_FUNC) &rnng_set_promise_context, 2},
   {"rnng_signal_thread_create", (DL_FUNC) &rnng_signal_thread_create, 2},
diff --git a/src/nanonext.h b/src/nanonext.h
index 949341e65..8e3cf9183 100644
--- a/src/nanonext.h
+++ b/src/nanonext.h
@@ -229,6 +229,7 @@ typedef struct nano_buf_s {
 
 extern void (*eln2)(void (*)(void *), void *, double, int);
 extern uint8_t special_bit;
+extern int nano_interrupt;
 
 extern SEXP nano_AioSymbol;
 extern SEXP nano_ContextSymbol;
@@ -326,6 +327,7 @@ SEXP rnng_dispatcher_socket(SEXP, SEXP, SEXP);
 SEXP rnng_eval_safe(SEXP);
 SEXP rnng_fini(void);
 SEXP rnng_get_opt(SEXP, SEXP);
+SEXP rnng_interrupt_switch(void);
 SEXP rnng_is_error_value(SEXP);
 SEXP rnng_is_nul_byte(SEXP);
 SEXP rnng_listen(SEXP, SEXP, SEXP, SEXP, SEXP);
@@ -350,7 +352,7 @@ SEXP rnng_request(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send_aio(SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_serial_config(SEXP, SEXP, SEXP, SEXP);
-SEXP rnng_set_marker(SEXP);
+SEXP rnng_set_marker(void);
 SEXP rnng_set_opt(SEXP, SEXP, SEXP);
 SEXP rnng_set_promise_context(SEXP, SEXP);
 SEXP rnng_signal_thread_create(SEXP, SEXP);
diff --git a/src/sync.c b/src/sync.c
index 629896499..c314f22de 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -623,3 +623,10 @@ SEXP rnng_socket_unlock(SEXP socket) {
   return nano_success;
 
 }
+
+SEXP rnng_interrupt_switch(void) {
+
+  nano_interrupt = nano_interrupt ? 0 : 1;
+  return R_NilValue;
+
+}
diff --git a/src/utils.c b/src/utils.c
index 648d110c0..276a74d65 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -607,10 +607,10 @@ SEXP rnng_serial_config(SEXP klass, SEXP sfunc, SEXP ufunc, SEXP vec) {
 
 }
 
-SEXP rnng_set_marker(SEXP x) {
+SEXP rnng_set_marker(void) {
 
-  special_bit = (uint8_t) NANO_INTEGER(x);
-  return x;
+  special_bit = special_bit ? (uint8_t) 0 : (uint8_t) 1;
+  return R_NilValue;
 
 }
 
diff --git a/tests/tests.R b/tests/tests.R
index 5d3e5469a..4a482dd58 100644
--- a/tests/tests.R
+++ b/tests/tests.R
@@ -212,12 +212,12 @@ test_print(p <- tryCatch(collect_pipe(r), error = function(e) NULL))
 if (!is.null(p)) test_class("nano", p)
 if (is_nano(p)) test_type("integer", p$id)
 if (is_nano(p)) test_type("integer", opt(p, "recv-fd"))
-test_true(.mark())
+test_null(.mark())
 test_class("sendAio", r <- send_aio(if (is_nano(p)) p else rep, "", timeout = 500))
 if (later) test_null(.keep(r, new.env()))
 test_error(collect_pipe(r), "valid")
 test_equal(req$recv(mode = 8L, block = 500)[4L], 1L)
-test_true(!.mark(FALSE))
+test_null(.mark())
 
 test_class("nanoContext", ctx <- context(rep))
 test_print(ctx)
@@ -550,12 +550,14 @@ test_zero(dial(s, url = "inproc://disp/1"))
 test_true(wait(cv))
 test_zero(send(disp, TRUE, block = 500L))
 test_true(recv(s, block = 500L))
-test_true(.mark())
+test_null(.mark())
 test_zero(send(s, NULL, block = 500L))
-test_true(!.mark(FALSE))
+test_null(.mark())
 test_null(recv(disp, block = 500L))
 test_zero(reap(s))
 rm(disp)
+test_null(.interrupt())
+test_null(.interrupt())
 
 test_equal(nanonext:::.DollarNames.ncurlAio(NULL, "sta"), "status")
 test_equal(nanonext:::.DollarNames.recvAio(NULL, "dat"), "data")