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value::to_number (3 of 3 overloads)
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Return the stored number cast to an arithmetic type.

Synopsis
template<
    class T>
T
to_number() const;
Description

This function attempts to return the stored value converted to the arithmetic type T which may not be bool:

  • If T is an integral type and the stored value is a number which can be losslessly converted, the conversion is performed without error and the converted number is returned.
  • If T is an integral type and the stored value is a number which cannot be losslessly converted, then the operation fails with an error.
  • If T is a floating point type and the stored value is a number, the conversion is performed without error. The converted number is returned, with a possible loss of precision.
  • Otherwise, if the stored value is not a number; that is, if this->is_number() returns false, then the operation fails with an error.
Constraints
std::is_arithmetic< T >::value && ! std::is_same< T, bool >::value
Complexity

Constant.

Return Value

The converted number.

Exceptions

Type

Thrown On

boost::system::system_error

Thrown on error.


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