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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_OPTIONAL_H
#define APR_OPTIONAL_H
#include "apu.h"
/**
* @file apr_optional.h
* @brief APR-UTIL registration of functions exported by modules
*/
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup APR_Util_Opt Optional Functions
* @ingroup APR_Util
*
* Typesafe registration and retrieval of functions that may not be present
* (i.e. functions exported by optional modules)
* @{
*/
/**
* The type of an optional function.
* @param name The name of the function
*/
#define APR_OPTIONAL_FN_TYPE(name) apr_OFN_##name##_t
/**
* Declare an optional function.
* @param ret The return type of the function
* @param name The name of the function
* @param args The function arguments (including brackets)
*/
#define APR_DECLARE_OPTIONAL_FN(ret,name,args) \
typedef ret (APR_OPTIONAL_FN_TYPE(name)) args
/**
* XXX: This doesn't belong here, then!
* Private function! DO NOT USE!
* @internal
*/
typedef void (apr_opt_fn_t)(void);
/** @internal */
APU_DECLARE_NONSTD(void) apr_dynamic_fn_register(const char *szName,
apr_opt_fn_t *pfn);
/**
* Register an optional function. This can be later retrieved, type-safely, by
* name. Like all global functions, the name must be unique. Note that,
* confusingly but correctly, the function itself can be static!
* @param name The name of the function
*/
#define APR_REGISTER_OPTIONAL_FN(name) do { \
APR_OPTIONAL_FN_TYPE(name) *apu__opt = name; \
apr_dynamic_fn_register(#name,(apr_opt_fn_t *)apu__opt); \
} while (0)
/** @internal
* Private function! DO NOT USE!
*/
APU_DECLARE(apr_opt_fn_t *) apr_dynamic_fn_retrieve(const char *szName);
/**
* Retrieve an optional function. Returns NULL if the function is not present.
* @param name The name of the function
*/
#define APR_RETRIEVE_OPTIONAL_FN(name) \
(APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* APR_OPTIONAL_H */
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