Question about Glib::ustring.

[Tao Wang <dancefire gmail com>]

Hi,

I'm not sure whether here is the right place for my question, I'm sorry if I'm wrong.

I have a class A, and one of its constructor use 'const Glib::ustring&' as parameter. So, I think any value of type 'char*', 'std::string', 'Glib::ustring' should be accepted by the constructor. And I have a function, one of its parameter is 'const A&'. Because I have the conversion constructor in A, so I think the function can accept the value of type 'char*', 'std::string', 'Glib::ustring' as parameter and automatically convert it to A.

However, the function can only accept the value of type 'A' or 'Glib::ustring' as parameter, it cannot automatically do the conversion of 'char*' and 'std::string'. I got following error message:

error: conversion from ‘const char [6]’ to non-scalar type ‘A’ requested
error: conversion from ‘std::string’ to non-scalar type ‘A’ requested
error: invalid initialization of reference of type ‘const A&’ from _expression_ of type ‘const char*’
error: invalid initialization of reference of type ‘const A&’ from _expression_ of type ‘std::string’

I extract the problem and posted the code here: 
http://pastebin.com/tMakRmSu

It looks like that I have to explicit convert them to A, which is not the way I want to, I hope those conversion can be implicit.

Could you help me figure out why my code is wrong? Why the automatically conversion doesn't work? How can I make those conversion implicit?
Thanks.

-- 
Regards

Tao Wang