diff --git a/stubs/core.stub b/stubs/core.stub
index f2b72c235b..75b24d1a6a 100644
--- a/stubs/core.stub
+++ b/stubs/core.stub
@@ -283,6 +283,17 @@ function str_ireplace($search, $replace, $subject, ?int &$count = null) {}
  */
 function stream_select(?array &$read, ?array &$write, ?array &$except, ?int $seconds, ?int $microseconds = null) {}
 
+/**
+ * @param int $error_code
+ * @param-out int $error_code
+ * @param string $error_message
+ * @param-out string $error_message
+ * @param int-mask<1, 2, 4> $flags
+ * @param resource|null $context
+ * @return resource|false
+ */
+function stream_socket_client(string $address, &$error_code = null, &$error_message = null, ?float $timeout = null, int $flags = 4, $context = null) {}
+
 /**
  * @param resource $stream
  * @param-out 0|1 $would_block