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I'm using the boost multiprecision library, and more precisely the boost::multiprecision::float128 type. Using ICPC for compiling, I get some errors when trying to to do something like:

double a = functionA();

where functionA() return a boost::multiprecision::float128 variable.

error: no suitable conversion function from "boost::multiprecision::float128" to "double" exists|

How can I solve this?

user1403546
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1 Answers1

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From the Boost documentation:

A number can be converted to any built in type, via the convert_to member function:

mpz_int z(2);
double i = z.convert_to<double>(); // sets i to 2

http://www.boost.org/doc/libs/1_57_0/libs/multiprecision/doc/html/boost_multiprecision/tut/conversions.html

Columbo
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Richard Critten
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  • thank you for your answer! Just another detail: since functionA() is a template function, and can returns a double or a boost::multiprecision::float128 variable, is there a way to keep the above syntax "double a = functionA();" but using your converter function? do I need to create a custom cast operator? – user1403546 Feb 03 '15 at 16:00