bslstl_isconvertibletocstring

Detailed Description

Provide a compile-time check for types convertible to C-string.

Outline

• Purpose
• Classes
• Description
  • Usage
    • Example 1: Determine If a Type Is Convertible to a C-String

Purpose

Provide a compile-time check for types convertible to C-string.

Classes

• bslstl::IsConvertibleToCString: meta-function for C-string convertibility

See also

bslmf_isconvertible, bslstl_isconvertibletostringview

Description

This component provides a meta-function, bslstl::IsConvertibleToCString, that may be used to query (at compile-time) whether a type is convertible to a C-string (i.e., const CHAR_TYPE *).

bslstl::IsConvertibleToCString meets the requirements of the UnaryTypeTrait concept defined in the C++ standard [meta.rqmts] with a base characteristic of bsl::true_type if the (template parameter) TYPE is convertible to const CHAR_TYPE *, and a base characteristic of bsl::false_type otherwise.

Usage

In this section we show the intended use of this component.

Example 1: Determine If a Type Is Convertible to a C-String

Suppose that we want to determine whether various types are convertible to C-strings (null-terminated character arrays).

First, we create a type that is convertible to const char *:

struct MyCStringWrapper {
    const char *d_str;
    operator const char *() const { return d_str; }
};

Now, we instantiate the bslstl::IsConvertibleToCString template for various types and verify the results:

assert( (bslstl::IsConvertibleToCString<char, const char *>::value));
assert( (bslstl::IsConvertibleToCString<char, MyCStringWrapper>::value));
assert(!(bslstl::IsConvertibleToCString<char, int>::value));
assert(!(bslstl::IsConvertibleToCString<char, void *>::value));