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Error C7034: an array cannot be initialized with a parenthesized initializer

Tags:

c++

visual-c++

v8

I am attempting to write a native Node addon that enumerates all windows on a Windows machine and returns an array of their titles to JS userland.

However I am stumped by this error:

C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(655): error C3074: an array cannot be initialized with a parenthesized initializer [C:\xampp\htdocs\enum-windows\build\enumWindows.vcxproj]

C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(773): note: see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,char(&)[255]>(_Objty (*),char (&)[255])' being comp iled with [ _Ty=char [255], _Objty=char [255] ]

To my knowledge I am not performing a parenthesised initialisation of an array?

#include <vector>
#include <node.h>
#include <v8.h>
#include <windows.h>
#include <stdio.h>

using namespace node;
using namespace v8;

BOOL CALLBACK EnumWindowsProc(HWND hWnd, LPARAM ptr) {
    std::vector<char[255]>* windowTitles =
        reinterpret_cast<std::vector<char[255]>*>(ptr);

    if (IsWindowVisible(hWnd)) {
        int size = GetWindowTextLength(hWnd);
        char buff[255];
        GetWindowText(hWnd, (LPSTR) buff, size);
        windowTitles->push_back(buff);
    }

    return true;
};

void GetWindowTexts(const FunctionCallbackInfo<Value>& args) {
    Isolate* isolate = Isolate::GetCurrent();
    HandleScope scope(isolate);
    Local<Array> arr = Array::New(isolate);
    std::vector<char[255]> windowTitles;

    EnumWindows(
        &EnumWindowsProc, 
        reinterpret_cast<LPARAM>(&windowTitles));

    for (unsigned int i = 0; i < windowTitles.size(); i++) {
        const char* ch = reinterpret_cast<const char*>(windowTitles.at(i));
        Local<String> str = String::NewFromUtf8(isolate, ch);
        arr->Set(i, str);
    }

    args.GetReturnValue().Set(arr);
}

void init(Handle<Object> exports, Handle<Object> module) {
    NODE_SET_METHOD(module, "exports", GetWindowTexts);
}

NODE_MODULE(enumWindows, init);

I believe the error has something to do with this line:

windowTitles->push_back(buff);

Perhaps my approach is naive.

like image 654
sdgluck Avatar asked Jun 23 '16 13:06

sdgluck


1 Answers

The problem arises here:

windowTitles->push_back(buff);

Because you cannot store an array in std::vector.

From the linked answer:

The objects stored by a standard library container must be copyable and assignable, and arrays are neither of these.

Perhaps use something like the following. The array has been replaced with std::array<char,255>:

BOOL CALLBACK EnumWindowsProc(HWND hWnd,LPARAM ptr)
{
    std::vector<std::array<char,255>>* windowTitles =
        reinterpret_cast<std::vector<std::array<char,255>>*>(ptr);

    if (IsWindowVisible(hWnd)) {
        int size = GetWindowTextLength(hWnd);
        std::array<char,255> buff;
        GetWindowText(hWnd,(LPWSTR)buff.data(),size);
        windowTitles->push_back(buff);
    }

    return true;
};
like image 109
wally Avatar answered Sep 28 '22 18:09

wally