Core: disabled SO_REUSEADDR on UDP sockets while testing config. On Linux, SO_REUSEADDR allows completely duplicate UDP sockets, so using SO_REUSEADDR when testing configuration results in packets being dropped if there is an existing traffic on the sockets being tested (ticket #2187). While dropped packets are expected with UDP, it is better to avoid this when possible. With this change, SO_REUSEADDR is no longer set on datagram sockets when testing configuration.

/*
 * Copyright (C) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


char *
ngx_dlerror(void)
{
    u_char         *p;
    static u_char   errstr[NGX_MAX_ERROR_STR];

    p = ngx_strerror(ngx_errno, errstr, NGX_MAX_ERROR_STR);
    *p = '\0';

    return (char *) errstr;
}