Assigning int32_t to std::string, should this be allowed?

Hi all, my compiler (gcc 4.4.3 on ubuntu 10.04 64bit server) is allowing me to assign an int32_t to a std::string object. The code is as follows:

Code:

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#include <stdint.h>
#include <iostream>
int main()
{
    int32_t i=1000000;
    std::string output;
    output=i;
    std::cout << output << std::endl;
    return 0;
}

---

which outputs:

Code:

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@

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Obviously, this isn't something I should be doing, but instead something that I was allowed to mistakenly do. I would have expected a compiler error saying that no assignment operator existed for integer to std::string. Instead what I believe is happening is that the compiler is implicitly converting int32_t to char, and then assigning the char to the string.

Is this a bug with the std::string class, with the compiler, or simply something I need to be more careful to avoid?

One of std::string's assignment operators takes one char parameter:

string::operator= - C++ Reference

int32_t is converted to char.

Quote:

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Originally Posted by frogger

Is this a bug with the std::string class, with the compiler, or simply something I need to be more careful to avoid?

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If you check, the length of output is 1, and 1000000%256 is 64, which is ascii for @. It isn't an implicit conversion, it's a straightforward assignment.

I would assume that's what it's supposed to do by the standard. I would call it a feature, but like all features, if you don't know about it, it could be confusing.

Quote:

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Originally Posted by MK27

It isn't an implicit conversion, it's a straightforward assignment.

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There isn't implicit conversion from char to std::string, but there is one from int32_t to char.

It's a narrowing conversion. Unfortunately, GCC doesn't warn about that (though Visual C++ does).

Thanks for the responses, I guess it makes sense if int32_t is being converted to char and char assignment to std::string is allowed. I wish gcc would at least warn about that conversion as Elysia reports Visual C++ does. Who knew MS would be more user friendly? :D