diff --git a/src/pulse/context.c b/src/pulse/context.c
index 3f7e6534f..a5d07ed93 100644
--- a/src/pulse/context.c
+++ b/src/pulse/context.c
@@ -1361,7 +1361,7 @@ pa_tagstruct *pa_tagstruct_command(pa_context *c, uint32_t command, uint32_t *ta
     return t;
 }
 
-uint32_t pa_context_get_index(pa_context *c) {
+uint32_t pa_context_get_index(const pa_context *c) {
     pa_assert(c);
     pa_assert(PA_REFCNT_VALUE(c) >= 1);
 
diff --git a/src/pulse/context.h b/src/pulse/context.h
index 7298a0879..dd90c21e7 100644
--- a/src/pulse/context.h
+++ b/src/pulse/context.h
@@ -256,7 +256,7 @@ pa_operation *pa_context_proplist_remove(pa_context *c, const char *const keys[]
  * identified in the server with. This is useful for usage with the
  * introspection functions, such as pa_context_get_client_info().
  * Returns PA_INVALID_INDEX on error. \since 0.9.11 */
-uint32_t pa_context_get_index(pa_context *s);
+uint32_t pa_context_get_index(const pa_context *s);
 
 /** Create a new timer event source for the specified time (wrapper
  * for mainloop->time_new). \since 0.9.16 */