libfcgi in multi threaded app

Hi there.

I'm having trouble with libfcgi and my multi threaded application.

I've created a socket via FCGX_OpenSocket. Everything all right.

Then, I'm creating threads (5, for example). In each thread, I'm
creating a request with FCGX_InitRequest (with socket, created early and
FCGI_FAIL_ACCEPT_ON_INTR).

Then the main loop starts. In this loop I'm calling FCGX_Accept_r on
this request. Here is trouble. Some of threads can successfully accept,
but some of then can't. Return code from FCGX_Accept is -9.

I've tried to setup mutex before and after FCGX_Accept_r, but it's not
helps ;-(

At the end of thread, I'm calling FCGX_Finish_r with 0 (don't destroy
socket, because it may be used by another thread).

What can I do? How to sync threads?

P.S. Single threaded apps works well ;-(

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