diff --git a/src/pulse/context.c b/src/pulse/context.c
index d298ae3ec..1f32421b8 100644
--- a/src/pulse/context.c
+++ b/src/pulse/context.c
@@ -1068,7 +1068,7 @@ pa_context_state_t pa_context_get_state(const pa_context *c) {
     return c->state;
 }
 
-int pa_context_errno(pa_context *c) {
+int pa_context_errno(const pa_context *c) {
 
     if (!c)
         return PA_ERR_INVALID;
diff --git a/src/pulse/context.h b/src/pulse/context.h
index 7a38ff238..37333fca7 100644
--- a/src/pulse/context.h
+++ b/src/pulse/context.h
@@ -190,7 +190,7 @@ void pa_context_set_state_callback(pa_context *c, pa_context_notify_cb_t cb, voi
 void pa_context_set_event_callback(pa_context *p, pa_context_event_cb_t cb, void *userdata);
 
 /** Return the error number of the last failed operation */
-int pa_context_errno(pa_context *c);
+int pa_context_errno(const pa_context *c);
 
 /** Return non-zero if some data is pending to be written to the connection */
 int pa_context_is_pending(pa_context *c);