log to log/error_log

#include "http_log.h"

ap_log_error(APLOG_MARK, int debug_level, 0, ap_server_conf, "%d pushing to queue_return", r);

#define APLOG_EMERG 0 /* system is unusable */
#define APLOG_ALERT 1 /* action must be taken immediately */
#define APLOG_CRIT 2 /* critical conditions */
#define APLOG_ERR 3 /* error conditions */
#define APLOG_WARNING 4 /* warning conditions */
#define APLOG_NOTICE 5 /* normal but significant condition */
#define APLOG_INFO 6 /* informational */
#define APLOG_DEBUG 7 /* debug-level messages */