c++ - Qt Creator 链接错误 : undefined reference to `KFUNC'

Question

) 我目前正在 Qt Creator 4.3.1 下开发一个项目，它需要一个外部库来使用键锁硬件设备。

该设备附带一张 CD，其中包含库 libkfunc64.so 和 libkfunc64.a(以及 32 位版本)，大概是为 C 编译的> 使用 gcc。我已经在虚拟程序中尝试了这些库，以检查它们是否有效，它们确实有效。

但是当我将重要的代码块添加到 Qt 项目中时，它会出现以下错误

 [...] error: undefined reference to `KFUNC(unsigned int, unsigned int, unsigned int, unsigned int)'

我已经尝试包含库

• 通过将库复制到系统目录并在 .pro 文件中简单地包含以下行

  LIBS += -lkfunc64

• 使用 .pro 文件中库的相对路径

  LIBS += -L$$PWD/../build-project/ -lkfunc64

  INCLUDEPATH += $$PWD/../build-Qmetrics-Desktop-Debug DEPENDPATH += $$PWD/../build-Qmetrics-Desktop-Debug

  # PRE_TARGETDEPS += $$PWD/../build-Qmetrics-Desktop-Debug/libkfunc64.a

但在尝试(重新)构建它时它一直显示此错误。我在互联网上阅读了几乎所有关于这个问题的主题，但没有一个能解决这个问题。

这是main.cpp的代码

#include "mainwindow.h"

#include <QApplication>
#include <QMessageBox>

// Key-lock stuff ----------
#define ValidateCode1 0X488B 
#define ValidateCode2 0XFEE2 
#define ValidateCode3 0XEF90
#define ClientIDCode1 0xB862 
#define ClientIDCode2 0x54CB 
#define ReadCode1     0X1772 
#define ReadCode2     0XC4E6
#define ReadCode3     0XBCF8

extern unsigned long KFUNC(unsigned, unsigned, unsigned, unsigned);
unsigned RotateLeft(unsigned, int);
void KTASK(unsigned, unsigned, unsigned, unsigned);
unsigned short ReturnValue1, ReturnValue2;
// -------------------------

int main(int argc, char *argv[])
{  
    KTASK(1, ValidateCode1, ValidateCode2, ValidateCode3);
    KTASK(RotateLeft(ReturnValue1, ReturnValue2 & 7) ^ ReadCode3 ^ ReturnValue2, RotateLeft(ReturnValue2, ReturnValue1 & 15), ReturnValue1 ^ ReturnValue2, 0);

    if ((ReturnValue1 == ClientIDCode1) && (ReturnValue2 == ClientIDCode2))
    {
        QApplication app(argc, argv);

        MainWindow w;
        w.showFullScreen();

        return app.exec();
    }
    else
    {
        QMessageBox msgBox;
        msgBox.setText("Wrong or missing key-lock!");
        return msgBox.exec();
    }
}

unsigned RotateLeft(unsigned Target, int Counts)
{
    int i;
    static unsigned LocalTarget, HighBit;
    LocalTarget = Target;
    for (i=0; i<Counts; i++)
    {
        HighBit = LocalTarget & 0X8000;
        LocalTarget = (LocalTarget << 1) + (HighBit >> 15);
    }
    LocalTarget = LocalTarget & 0XFFFF; /* For 32 bit integers */
    return (LocalTarget);
}

void KTASK(unsigned CommandCode, unsigned Argument2, unsigned Argument3, unsigned Argument4)
{
  unsigned long int ReturnValue;
  ReturnValue = KFUNC(CommandCode, Argument2, Argument3, Argument4); // <--- this is the only function that is used from the external library
  ReturnValue1 = (unsigned) (ReturnValue & 0XFFFF);
  ReturnValue2 = (unsigned) (ReturnValue >> 16);
}

.pro 文件的(相关部分)如下

# Adds OpenCV, DC1394 and Keylok libraries
unix {
    CONFIG += link_pkgconfig
    PKGCONFIG += opencv
    LIBS += -ldc1394 -lkfunc64
}

我真的不知道该怎么办:'(

Answer 1

您是否尝试过使用 extern "C"声明函数？

例如:

#ifdef __cplusplus
extern "C"
{
#endif

   extern unsigned long KFUNC(unsigned, unsigned, unsigned, unsigned);

#ifdef __cplusplus
};
#endif

这是从 C++ 调用外部 C 函数所必需的。