--- a/src/os/unix/ngx_thread.h
+++ b/src/os/unix/ngx_thread.h
@@ -36,6 +36,11 @@ typedef volatile struct {
 } ngx_mutex_t;
 
 
+typedef struct {
+    ngx_mutex_t   mutex;
+} ngx_cv_t;
+
+
 #define ngx_thread_sigmask(how, set, oset)                         \
             (sigprocmask(how, set, oset) == -1) ? ngx_errno : 0
 
@@ -102,6 +107,12 @@ ngx_int_t ngx_mutex_dolock(ngx_mutex_t *
 ngx_int_t ngx_mutex_unlock(ngx_mutex_t *m);
 
 
+ngx_cv_t *ngx_cv_init(ngx_log_t *log);
+void ngx_cv_done(ngx_cv_t *cv);
+ngx_int_t ngx_cv_wait(ngx_cv_t *cv);
+ngx_int_t ngx_cv_signal(ngx_cv_t *cv);
+
+
 #else /* !NGX_THREADS */
 
 #define ngx_thread_volatile