Detailed Description

Outline

Purpose
Classes
Description
- Usage
  - Example 1: Verify Arithmetic Types

Purpose

Provide a compile-time check for determining arithmetic types.

Classes

bsl::is_arithmetic: standard meta-function for determining arithmetic types
bsl::is_arithmetic_v: the result value of bsl::is_arithmetic

See also: bslmf_integralconstant

Description

This component defines a meta-function, bsl::is_arithmetic and a template variable bsl::is_arithmetic_v that represents the result value of the bsl::is_arithmetic meta-function, that may be used to query whether a template parameter type is an arithmetic type.

bsl::is_arithmetic meets the requirements of the is_arithmetic template defined in the C++11 standard [meta.unary.comp].

Note that the template variable is_arithmetic_v is defined in the C++17 standard as an inline variable. If the current compiler supports the inline variable C++17 compiler feature, bsl::is_arithmetic_v is defined as an inline constexpr bool variable. Otherwise, if the compiler supports the variable templates C++14 compiler feature, bsl::is_arithmetic_v is defined as a non-inline constexpr bool variable. See BSLS_COMPILERFEATURES_SUPPORT_INLINE_VARIABLES and BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES macros in bsls_compilerfeatures component for details.

Usage

In this section we show intended use of this component.

Example 1: Verify Arithmetic Types

Suppose that we want to assert whether a set of types are arithmetic types.

Now, we instantiate the bsl::is_arithmetic template for these types, and assert the value static data member of each instantiation:

assert(false == bsl::is_arithmetic<int& >::value);
assert(false == bsl::is_arithmetic<int *>::value);
assert(true  == bsl::is_arithmetic<int  >::value);

Note that if the current compiler supports the variable templates C++14 feature then we can re-write the snippet of code above using the bsl::is_arithmetic_v variable as follows:

#ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
  assert(false == bsl::is_arithmetic_v<int& >);
  assert(false == bsl::is_arithmetic_v<int *>);
  assert(true  == bsl::is_arithmetic_v<int  >);
#endif