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/* Copyright 2001-2005 The Apache Software Foundation or its licensors, as
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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#ifndef APR_OPTIONAL_H
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#define APR_OPTIONAL_H
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* @file apr_optional.h
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* @brief APR-UTIL registration of functions exported by modules
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* @defgroup APR_Util_Opt Optional Functions
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* Typesafe registration and retrieval of functions that may not be present
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* (i.e. functions exported by optional modules)
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* The type of an optional function.
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* @param name The name of the function
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#define APR_OPTIONAL_FN_TYPE(name) apr_OFN_##name##_t
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* Declare an optional function.
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* @param ret The return type of the function
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* @param name The name of the function
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* @param args The function arguments (including brackets)
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#define APR_DECLARE_OPTIONAL_FN(ret,name,args) \
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typedef ret (APR_OPTIONAL_FN_TYPE(name)) args
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* XXX: This doesn't belong here, then!
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* Private function! DO NOT USE!
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typedef void (apr_opt_fn_t)(void);
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APU_DECLARE_NONSTD(void) apr_dynamic_fn_register(const char *szName,
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* Register an optional function. This can be later retrieved, type-safely, by
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* name. Like all global functions, the name must be unique. Note that,
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* confusingly but correctly, the function itself can be static!
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* @param name The name of the function
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#define APR_REGISTER_OPTIONAL_FN(name) do { \
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APR_OPTIONAL_FN_TYPE(name) *apu__opt = name; \
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apr_dynamic_fn_register(#name,(apr_opt_fn_t *)apu__opt); \
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* Private function! DO NOT USE!
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APU_DECLARE(apr_opt_fn_t *) apr_dynamic_fn_retrieve(const char *szName);
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* Retrieve an optional function. Returns NULL if the function is not present.
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* @param name The name of the function
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#define APR_RETRIEVE_OPTIONAL_FN(name) \
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(APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)
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#endif /* APR_OPTIONAL_H */