Question

我对gcc 5.1.0有一个奇怪的问题。以下最小代码

#!/usr/bin/env phantomjs 
function waitFor(testFx, onReady, timeOutMillis) {
var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 5000, //< Default Max Timout is 5s
    start = new Date().getTime(),
    condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()), //< defensive code
    interval = setInterval(function() {
        if ( (new Date().getTime() - start < maxtimeOutMillis) && !condition ) {
            // If not time-out yet and condition not yet fulfilled
            condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()); //< defensive code
        } else {
            if(!condition) {
                // If condition still not fulfilled (timeout but condition is 'false')
                console.log("'waitFor()' timeout");
                phantom.exit(1);
            } else {
                // Condition fulfilled (timeout and/or condition is 'true')
                console.log("'waitFor()' finished in " + (new Date().getTime() - start) + "ms.");
                typeof(onReady) === "string" ? eval(onReady) : onReady(); //< Do what it's supposed to do once the condition is fulfilled
                clearInterval(interval); //< Stop this interval
            }
        }
    }, 500); //repeat check every 500ms
};

var system = require('system')
var width = window.parseInt(system.args[1])
var height = window.parseInt(system.args[2])
var url = system.args[3]
var relative_path = system.args[4]

var page = require('webpage').create();
var resources = [];

page.onResourceRequested = function(request) {
  resources[request.id] = request.stage;
};

page.onResourceReceived = function(response) {
  resources[response.id] = response.stage;
};

page.onResourceError = function(resourceError) {
    page.reason = resourceError.errorString;
    page.reason_url = resourceError.url;
};

//Loading whole webpage
page.viewportSize = {
  width: 2000,
  height: 10000
};

page.open(url, function(status) {
  if (status !== 'success') {
    console.log("Error opening url \"" + page.reason_url + "\": " +                  page.reason );
  } else {
    waitFor(function() {
      page.viewportSize = { width: width, height: height };
      page.render(relative_path);
    }, 10000);
  }
  phantom.exit();
});

导致编译器错误

// header 1
namespace A {
  template<typename X>
  inline constexpr X square(X x) { return x*x; }
}
// header 2
namespace A { namespace B {
    template<typename X>
    struct matrix { X A[3][3]; };
    template<typename X>
    matrix<X> square(matrix<X> const&) noexcept;
} }
// source, includes both headers
namespace A { namespace B {
    using A::square;         // no problem without this line
    template<typename X>
    matrix<X> square(matrix<X> const&M) noexcept
    {
      matrix<X> R;
      for(int i=0; i!=3; ++i)
        for(int j=0; j!=3; ++j)
          R.A[i][j] = M.A[i][0]*M.A[0][j] +
                      M.A[i][1]*M.A[1][j] +
                      M.A[i][2]*M.A[2][j] ;
      return R;
    }
    template matrix<double> square(matrix<double> const&) noexcept;
} }

如果删除了源中指示的行，则错误消失。代码用clang ++编译好，但gcc 4.8也显示错误。我试图在gcc bugzilla找到相关的错误报告但没有成功，但这可能没有任何意义。所以我的主要问题是：这确实是一个gcc bug，如果是的话，它是新的吗？

这可能与古代bug 37374有关，它显示了没有模板的相似行为。我已经提交了一份新的bug report。

gcc：在命名空间范围内使用声明阴影重载

0 个答案: