Std::getline on windows

Question

I have the following code:

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

using namespace std;

int main() {
    // your code goes here
    stringstream instream("a x b c d x c d");
    string line;
    bool loop;
    loop = getline(instream, line);
    return 0;
}

It works on gcc, but when I compile using Visual Studio 2013 I get the build error at loop = getline(instream, line):

cannot convert from 'std::basic_istream<char, std::char_traits<char> > to 'bool'

How do I fix this problem?

Depends. What are you trying to do? What is the purpose of `loop`? — Lightness Races in Orbit, Sep 14 '15 at 19:45
I want to know if file is ending or not. Again this is minimal code generated from a bigger project. — Dzung Nguyen, Sep 14 '15 at 19:47
GCC what? There have been hundreds of GCCs. What are your compilation commands? Y'know, the nitty gritty. — Lightness Races in Orbit, Sep 14 '15 at 19:52

score 2 · Accepted Answer · edited May 23 '17 at 12:29

2

Implicit boolean conversion rules changed from C++03 to C++11, and compiler support for this stuff varies hugely across platforms.

If you really need this, I'd use the old force-boolean trick:

loop = !!getline(instream, line);

You don't need the trick if you plonk getline into an if conditional directly, instead of first assigning it to a variable, because if is special.

edited May 23 '17 at 12:29

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answered Sep 14 '15 at 19:50

Lightness Races in Orbit

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Std::getline on windows

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