Qt链接器错误窗口

时间:2015-10-30 18:32:57

标签: c++ qt linker

我正在尝试运行此代码,但我得到的只是链接器错误,并且不知道该做什么或我在这里做错了什么。现在已经挣扎太久了,任何帮助都非常感激,所以我可以把这件事情推进去。这也是我有史以来的第一个Qt应用程序。

运行Qt Creator 3.5.1,基于Qt 5.5.1(MSVC 2013,32位) 编译器:Microsoft Visual C ++编译器12.0 操作系统:Windows 8.1 Pro 64位

我有Qt项目,我有文件:

Hasher.h

#ifndef HASHER_H
#define HASHER_H

#include <QString>
#include <QCryptographicHash>

class Hasher : public QCryptographicHash
{
public:
    Hasher(const QByteArray &data, Algorithm method); /* Constructor */
    ~Hasher(); /* Destructor */

    QString name, output;
private:
    QCryptographicHash *QCryptObject;
};

#endif // HASHER_H

Hasher.cpp

#include "hasher.h"

/* Destructor */
Hasher::~Hasher() {

}

/*
 * Constructor Hasher(QByteArray &, Algorithm) generates hash
 * from given input with given algorithm-method
*/
Hasher::Hasher(const QByteArray &data, Algorithm method) {
   QByteArray result = this->QCryptObject->hash(data, method);
   this->output = result.toHex();
}

的main.cpp

#include <QCoreApplication>
#include <QString>
#include <QFile>
#include <QDebug>

#include "hasher.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QString fileName;
    QTextStream stream(stdin);

    qDebug() << "MD5 generator!" << endl;
    qDebug() << "Give filename to generate checksum from: ";
    fileName = stream.readLine();
    QFile* file = new QFile(fileName);
        if(file->open(QIODevice::ReadOnly))
            {
                Hasher hasher(file->readAll(), QCryptographicHash::Md5);
                qDebug() << "MD5 Hash of " << fileName << " is: " << hasher.output << endl;
                file->close();
            }
    return a.exec();
}

我得到的错误:

main.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl Hasher::Hasher(class QByteArray const &,enum QCryptographicHash::Algorithm)" (??0Hasher@@QEAA@AEBVQByteArray@@W4Algorithm@QCryptographicHash@@@Z) referenced in function main

main.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl Hasher::~Hasher(void)" (??1Hasher@@QEAA@XZ) referenced in function main

debug\MD5-generator.exe:-1: error: LNK1120: 2 unresolved externals

.pro文件

QT += core
QT -= gui

TARGET = MD5-generator
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp \
    hasher.cpp

HEADERS += \
    hasher.h

2 个答案:

答案 0 :(得分:3)

因此,链接器错误是由未更新的makefile和目标文件引起的,因为新的Hasher.cpp根本没有被编译。在这种情况下,重建项目可能有所帮助:CleanRun qmakeBuild

答案 1 :(得分:2)

Hasher::Hasher中,您需要调用基类构造函数:

Hasher::Hasher(const QByteArray &data, Algorithm method)
    : QCryptographicHash(method)
{
   QByteArray result = this->hash(data, method);
   this->output = result.toHex();
}

我不知道为什么MSVC根本编译该代码,它甚至不应该链接。