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diff --git a/include/apr_queue.h b/include/apr_queue.h
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+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef APR_QUEUE_H
+#define APR_QUEUE_H
+
+/**
+ * @file apr_queue.h
+ * @brief Thread Safe FIFO bounded queue
+ * @note Since most implementations of the queue are backed by a condition
+ * variable implementation, it isn't available on systems without threads.
+ * Although condition variables are sometimes available without threads.
+ */
+
+#include "apu.h"
+#include "apr_errno.h"
+#include "apr_pools.h"
+
+#if APR_HAS_THREADS
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * @defgroup APR_Util_FIFO Thread Safe FIFO bounded queue
+ * @ingroup APR_Util
+ * @{
+ */
+
+/**
+ * opaque structure
+ */
+typedef struct apr_queue_t apr_queue_t;
+
+/** 
+ * create a FIFO queue
+ * @param queue The new queue
+ * @param queue_capacity maximum size of the queue
+ * @param a pool to allocate queue from
+ */
+APU_DECLARE(apr_status_t) apr_queue_create(apr_queue_t **queue, 
+                                           unsigned int queue_capacity, 
+                                           apr_pool_t *a);
+
+/**
+ * push/add an object to the queue, blocking if the queue is already full
+ *
+ * @param queue the queue
+ * @param data the data
+ * @returns APR_EINTR the blocking was interrupted (try again)
+ * @returns APR_EOF the queue has been terminated
+ * @returns APR_SUCCESS on a successful push
+ */
+APU_DECLARE(apr_status_t) apr_queue_push(apr_queue_t *queue, void *data);
+
+/**
+ * pop/get an object from the queue, blocking if the queue is already empty
+ *
+ * @param queue the queue
+ * @param data the data
+ * @returns APR_EINTR the blocking was interrupted (try again)
+ * @returns APR_EOF if the queue has been terminated
+ * @returns APR_SUCCESS on a successful pop
+ */
+APU_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data);
+
+/**
+ * push/add an object to the queue, returning immediately if the queue is full
+ *
+ * @param queue the queue
+ * @param data the data
+ * @returns APR_EINTR the blocking operation was interrupted (try again)
+ * @returns APR_EAGAIN the queue is full
+ * @returns APR_EOF the queue has been terminated
+ * @returns APR_SUCCESS on a successful push
+ */
+APU_DECLARE(apr_status_t) apr_queue_trypush(apr_queue_t *queue, void *data);
+
+/**
+ * pop/get an object to the queue, returning immediately if the queue is empty
+ *
+ * @param queue the queue
+ * @param data the data
+ * @returns APR_EINTR the blocking operation was interrupted (try again)
+ * @returns APR_EAGAIN the queue is empty
+ * @returns APR_EOF the queue has been terminated
+ * @returns APR_SUCCESS on a successful pop
+ */
+APU_DECLARE(apr_status_t) apr_queue_trypop(apr_queue_t *queue, void **data);
+
+/**
+ * returns the size of the queue.
+ *
+ * @warning this is not threadsafe, and is intended for reporting/monitoring
+ * of the queue.
+ * @param queue the queue
+ * @returns the size of the queue
+ */
+APU_DECLARE(unsigned int) apr_queue_size(apr_queue_t *queue);
+
+/**
+ * interrupt all the threads blocking on this queue.
+ *
+ * @param queue the queue
+ */
+APU_DECLARE(apr_status_t) apr_queue_interrupt_all(apr_queue_t *queue);
+
+/**
+ * terminate the queue, sending an interrupt to all the
+ * blocking threads
+ *
+ * @param queue the queue
+ */
+APU_DECLARE(apr_status_t) apr_queue_term(apr_queue_t *queue);
+
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
+
+#endif /* APR_HAS_THREADS */
+
+#endif /* APRQUEUE_H */