diff --git a/src/pulse/context.c b/src/pulse/context.c
index 1f32421b8..c5850979b 100644
--- a/src/pulse/context.c
+++ b/src/pulse/context.c
@@ -1591,7 +1591,7 @@ finish:
         pa_proplist_free(pl);
 }
 
-pa_time_event* pa_context_rttime_new(pa_context *c, pa_usec_t usec, pa_time_event_cb_t cb, void *userdata) {
+pa_time_event* pa_context_rttime_new(const pa_context *c, pa_usec_t usec, pa_time_event_cb_t cb, void *userdata) {
     struct timeval tv;
 
     pa_assert(c);
diff --git a/src/pulse/context.h b/src/pulse/context.h
index 37333fca7..665e9f835 100644
--- a/src/pulse/context.h
+++ b/src/pulse/context.h
@@ -260,7 +260,7 @@ uint32_t pa_context_get_index(pa_context *s);
 
 /** Create a new timer event source for the specified time (wrapper
  * for mainloop->time_new). \since 0.9.16 */
-pa_time_event* pa_context_rttime_new(pa_context *c, pa_usec_t usec, pa_time_event_cb_t cb, void *userdata);
+pa_time_event* pa_context_rttime_new(const pa_context *c, pa_usec_t usec, pa_time_event_cb_t cb, void *userdata);
 
 /** Restart a running or expired timer event source (wrapper for
  * mainloop->time_restart). \since 0.9.16 */