Merge remote-tracking branch 'origin/master'

src/process.cpp

@@ -110,7 +110,8 @@ namespace proc {
 
       // We always call terminate() even if we waited successfully for all processes above.
       // This ensures the process group state is consistent with the OS in boost.
-      group.terminate();
+      std::error_code ec;
+      group.terminate(ec);
       group.detach();
     }
 
@@ -462,6 +463,16 @@ namespace proc {
 
   int
   proc_t::running() {
+#ifndef _WIN32
+    // On POSIX OSes, we must periodically wait for our children to avoid
+    // them becoming zombies. This must be synchronized carefully with
+    // calls to bp::wait() and platf::process_group_running() which both
+    // invoke waitpid() under the hood.
+    auto reaper = util::fail_guard([]() {
+      while (waitpid(-1, nullptr, WNOHANG) > 0);
+    });
+#endif
+
     if (placebo) {
       return _app_id;
     }