Provide a compile-time check for integral types.
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Detailed Description
- Outline
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- Purpose:
- Provide a compile-time check for integral types.
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- Classes:
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- See also:
- Component bslmf_integralconstant
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- Description:
- This component defines a meta-function,
bsl::is_integral
and a template variable bsl::is_integral_v
, that represents the result value of the bsl::is_integral
meta-function, that may be used to query whether a type is an integral type as defined in section 3.9.1.7 of the C++11 standard [basic.fundamental] (excluding those types that were introduced in C++11).
bsl::is_integral
meets the requirements of the is_integral
template defined in the C++11 standard [meta.unary.cat] except that it may not correctly evaluate types introduced in C++11.
- Note that the template variable
is_integral_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_integral_v
is defined as an inline constexpr bool
variable. Otherwise, if the compiler supports the variable templates C++14 compiler feature, bsl::is_integral_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.
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- Usage:
- In this section we show intended use of this component.
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- Example 1: Verify Integral Types:
- Suppose that we want to assert whether a particular type is an integral type.
- First, we create two
typedef
s -- an integral type and a non-integral type: typedef void MyType;
typedef int MyIntegralType;
Now, we instantiate the bsl::is_integral
template for each of the typedef
s and assert the value
static data member of each instantiation: 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_integral_v
variable as follows: #ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
assert(false == bsl::is_integral_v<MyType>);
assert(true == bsl::is_integral_v<MyIntegralType>);
#endif