How do I make interface for std::pair<> with no default constructor in swig and Python?

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Hi all,
I'm going to implement std::pair<T, U> in swig&python.
T is class and it doesn't have default constructor.
When I make wrapper.cxx via swig, it has a compile error that

error C2512: 'T' : no appropriate default constructor available

It occurs because when create std::pair variable, it calls constructors of T and U.

How can I fix it?

What I have tried:

I have tried to add code following this:

%feature("valuewrapper") std::pair<T, U>;
%ignore std::pair<T, U>::pair();

But it has no effect.

Posted 30-Mar-17 16:39pm

Member 11612662

Updated 31-Mar-17 1:21am

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Jochen Arndt · Answer 1 · 2017-03-31T01:21:00

Solution 1

I don't know swig but you got a C++ compiler error.

T and U are template parameters that must be replaced with existing class types.
C++ Examples:

std::pair <int, int> p1;
std::pair <int, std::string> p2;

See also pair::pair - C++ Reference[^].

So you have to use it accordingly depending on the types used with std::pair (guessed):

%feature("valuewrapper") std::pair <int, int>;
%ignore std::pair<int, int>::pair();

%feature("valuewrapper") std::pair <int, std::string>;
%ignore std::pair<int, std::string>::pair();

Posted 31-Mar-17 1:21am

Jochen Arndt

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Member 11612662 31-Mar-17 21:12pm

I tried it.
std::pair<MyClass1, MyStruct1>;
But it have no effect.

Jochen Arndt 1-Apr-17 3:01am

Sorry about that. I have not used swig and can not help more.

But the compiler error is gone?

Member 11612662 2-Apr-17 20:55pm

Thanks for your advice. But error still exist.