// bslmf_removecv.h -*-C++-*- #ifndef INCLUDED_BSLMF_REMOVECV #define INCLUDED_BSLMF_REMOVECV #include <bsls_ident.h> BSLS_IDENT("$Id: $") //@PURPOSE: Provide a meta-function for removing top-level cv-qualifiers. // //@CLASSES: // bsl::remove_cv: meta-function for removing top-level cv-qualifiers // bsl::remove_cv_t: alias to the return type of the meta-function // //@SEE_ALSO: bslmf_addcv // //@DESCRIPTION: This component defines a meta-function, 'bsl::remove_cv', and // declares a 'bsl::remove_cv_t' alias to the return type of the // 'bsl::remove_cv', that may be used to remove any top-level cv-qualifiers // ('const'-qualifier and 'volatile'-qualifier) from a type. // // 'bsl::remove_cv' and 'bsl::remove_cv_t' meet the requirements of the // 'remove_cv' template defined in the C++11 standard [meta.trans.cv]. // ///Usage ///----- // In this section we show intended use of this component. // ///Example 1: Removing the CV-Qualifiers of a Type ///- - - - - - - - - - - - - - - - - - - - - - - - // Suppose that we want to remove the cv-qualifiers from a particular type. // // First, we create two 'typedef's -- a 'const'-qualified and // 'volatile'-qualified type ('MyCvType') and the same type without the // cv-qualifiers ('MyType'): //.. // typedef int MyType; // typedef const volatile int MyCvType; //.. // Now, we remove the cv-qualifiers from 'MyCvType' using 'bsl::remove_cv' and // verify that the resulting type is the same as 'MyType': //.. // assert(true == (bsl::is_same<bsl::remove_cv<MyCvType>::type, // MyType>::value)); //.. // Finally, if the current compiler supports alias templates C++11 feature, we // remove a 'const'-qualified and 'volatile'-qualifier from 'MyCvType' using //'bsl::remove_cv_t' and verify that the resulting type is the same as // 'MyType': //.. //#ifdef BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES // assert(true == // (bsl::is_same<bsl::remove_cv_t<MyCvType>, MyType>::value)); //#endif //.. // Note, that the 'bsl::remove_cv_t' avoids the '::type' suffix and 'typename' // prefix when we want to use the result of the 'bsl::remove_cv' meta-function // in templates. #include <bslscm_version.h> #include <bslmf_removeconst.h> #include <bslmf_removevolatile.h> #include <bsls_compilerfeatures.h> namespace bsl { // ================ // struct remove_cv // ================ template <class t_TYPE> struct remove_cv { // This 'struct' template implements the 'remove_cv' meta-function defined // in the C++11 standard [meta.trans.cv], providing an alias, 'type', that // returns the result. 'type' has the same type as the (template // parameter) 't_TYPE' except that any top-level cv-qualifiers have been // removed. // PUBLIC TYPES typedef typename remove_const<typename remove_volatile<t_TYPE>::type>::type type; // This 'typedef' is an alias to the same type as the (template // parameter) 't_TYPE' except that any top-level cv-qualifier has been // removed. }; #ifdef BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES // ALIASES template <class t_TYPE> using remove_cv_t = typename remove_cv<t_TYPE>::type; // 'remove_cv_t' is an alias to the return type of the 'bsl::remove_cv' // meta-function. Note, that the 'remove_cv_t' avoids the '::type' suffix // and 'typename' prefix when we want to use the result of the // meta-function in templates. #endif // BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES } // close namespace bsl #endif // ---------------------------------------------------------------------------- // Copyright 2013 Bloomberg Finance L.P. // // Licensed 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. // ----------------------------- END-OF-FILE ----------------------------------