Component bslmf_removecvref [Package bslmf]

Provide a meta-func for removing reference-ness and cv-qualifiers. More...

Classes
struct	bsl::remove_cvref< t_TYPE >

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Detailed Description

Outline

• Purpose
• Classes
• Description
  • Usage
    • Example 1: Removing the CV-Qualifiers and Reference-ness of a Type

Purpose:

Provide a meta-func for removing reference-ness and cv-qualifiers.

Classes:

bsl::remove_cvref	meta-func for removing reference-ness and cv-qualifiers
bsl::remove_cvref_t	alias to the return type of the meta-function

See also:

Component bslmf_removecv, Component bslmf_removereference

Description:

This component defines a meta-function, bsl::remove_cvref, and declares a bsl::remove_cvref_t alias to the return type of the bsl::remove_cvref, that may be used to strip reference-ness (including both lvalue and rvalue reference-ness, if the latter is supported by the compiler) and to remove any top-level cv-qualifiers (const-qualifier and volatile-qualifier) from a type.

bsl::remove_cvref and bsl::remove_cvref_t meet the requirements of the remove_cvref template defined in the C++20 standard [meta.trans.other].

Usage:

In this section we show intended use of this component.

Example 1: Removing the CV-Qualifiers and Reference-ness of a Type:

Suppose that we want to remove the cv-qualifiers from a particular type.

First, we create two typedefs -- a const-qualified and volatile-qualified reference type (MyCvRefType) and the same type without the cv-qualifiers and reference-ness (MyType):

      typedef const volatile int& MyCvRefType;
      typedef                int  MyType;

Now, we remove the cv-qualifiers from MyCvRefType and its reference-ness using bsl::remove_cvref and verify that the resulting type is the same as MyType:

      assert(true == (bsl::is_same<bsl::remove_cvref<MyCvRefType>::type,
                                   MyType>::value));

Finally, if the current compiler supports alias templates C++11 feature, we remove a const-qualifier, volatile-qualifier and its reference-ness from MyCvRefType using bsl::remove_cvref_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_cvref_t<MyCvRefType>, MyType>::value));
#endif