C++ 链接器错误 undefined reference to a class definition and its member functions on Linux

Question

我正在尝试在 Linux 上安装 QScintilla-gpl-2.7.12.6.32-279。 #1 SMP 2012 x86_64 x86_64 x86_64 GNU/Linux

我已经在上一篇文章中解决了这个问题。但是，我遇到了链接器错误的新问题:

花了我一周的时间还是找不到原因。

即使我试过了，旧帖子也帮不了我。任何帮助将不胜感激。

链接命令:

$(TARGET):  $(OBJECTS)
  $(LINK) $(LFLAGS) -o $(TARGET) $(LIBS) $(OBJECTS)  $(LIBS_SUFFIX) $(OBJCOMP)

OBJECTS       = ListBoxQt.o \
    PlatQt.o \
    qsciabstractapis.o \
    qsciapis.o \
    ..........

 LIBS          = -L/home/user/myPath/qt483/qt-everywhere-opensource-src-4.8.3/lib
 LFLAGS        = -Wl,-O1
 LINK          = g++
 LIBS_SUFFIX   = -lQtCore -lQtGui -lQt3Support -lQtCLucene -lQtDeclarative -lQtDesigner  -lQtDesignerComponents -    lQtHelp -lQtMultimedia -lQtNetwork -lQtOpenGL -lQtScript - lQtScriptTools -lQtSql -lQtSvg -lQtTest -lQtWebKit -lQtXml -lQtXmlPatterns -lpthread
 OBJCOMP is not defined. 

谢谢

错误:

qscintilla2/QScintilla-gpl-2.7.1/src/Indicator.o: In function `Indicator::Draw(Surface*, PRectangle const&, PRectangle const&)':
Indicator.cpp:(.text+0x409): undefined reference to `RGBAImage::RGBAImage(int, int,    float, unsigned char const*)'
Indicator.cpp:(.text+0x43d): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x456): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x47a): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x493): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x4ac): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x4c7): undefined reference to `RGBAImage::Pixels() const'
Indicator.cpp:(.text+0x50f): undefined reference to `RGBAImage::~RGBAImage()'
Indicator.cpp:(.text+0x900): undefined reference to `RGBAImage::RGBAImage(int, int, float, unsigned char const*)'
Indicator.cpp:(.text+0x94e): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0x9f9): undefined reference to `RGBAImage::SetPixel(int, int, ColourDesired, int)'
Indicator.cpp:(.text+0xa4b): undefined reference to `RGBAImage::Pixels() const'
Indicator.cpp:(.text+0xac7): undefined reference to `RGBAImage::~RGBAImage()'
/qscintilla2/QScintilla-gpl-2.7.1/src/LineMarker.o: In function  `LineMarker::Draw(Surface*, PRectangle&, Font&, LineMarker::typeOfFold, int)':
LineMarker.cpp:(.text+0x2fd): undefined reference to `RGBAImage::Pixels() const'
LineMarker.cpp:(.text+0x3e3): undefined reference to `XPM::Draw(Surface*, PRectangle&)'
qscintilla2/QScintilla-gpl-2.7.1/src/LineMarker.o: In function  `LineMarker::SetRGBAImage(Point, float, unsigned char const*)':
LineMarker.cpp:(.text+0x1648): undefined reference to `RGBAImage::RGBAImage(int, int,  float, unsigned char const*)'
qscintilla2/QScintilla-gpl-2.7.1/src/LineMarker.o: In function `LineMarker::SetXPM(char const* const*)':
LineMarker.cpp:(.text+0x16c6): undefined reference to `XPM::XPM(char const* const*)'
qscintilla2/QScintilla-gpl-2.7.1/src/LineMarker.o: In function `LineMarker::SetXPM(char const*)':
LineMarker.cpp:(.text+0x1746): undefined reference to `XPM::XPM(char const*)'
collect2: ld returned 1 exit status

make: * [Qt4Qt5] 错误 1

src/XPM.h 中类 RGBAImage 的定义。

没有编译错误，但是链接器找不到XPM.h中定义的RGBAImage，它已经包含在Indicator.cpp和Indicator.cpp中。

在 Makefile 中，Indicator.o 和 Indicator.o 可以毫无问题地生成，并且已放入链接器输入参数列表中，但链接器错误仍然存​​在。没有 XPM.cpp 文件。但是即使我创建了一个包含 XPM.h 的 XPM.cpp 文件并得到了 XPM.o，我也遇到了同样的错误。

#include <vector>
#include <map>

#include "Platform.h"

#include "Scintilla.h"
#include "XPM.h" // RGBAImage is defined here
#include "Indicator.h"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

static PRectangle PixelGridAlign(const PRectangle &rc) {
// Move left and right side to nearest pixel to avoid blurry visuals
return PRectangle(int(rc.left + 0.5), rc.top, int(rc.right + 0.5), rc.bottom);
}

void Indicator::Draw(Surface *surface, const PRectangle &rc, const PRectangle &rcLine)     
{
surface->PenColour(fore);
int ymid = (rc.bottom + rc.top) / 2;
if (style == INDIC_SQUIGGLE) {
    int x = int(rc.left+0.5);
    int xLast = int(rc.right+0.5);
    int y = 0;
    surface->MoveTo(x, rc.top + y);
    while (x < xLast) {
        if ((x + 2) > xLast) {
            if (xLast > x)
                y = 1;
            x = xLast;
        } else {
            x += 2;
            y = 2 - y;
        }
        surface->LineTo(x, rc.top + y);
    }
} else if (style == INDIC_SQUIGGLEPIXMAP) {
    PRectangle rcSquiggle = PixelGridAlign(rc);

    int width = Platform::Minimum(4000, rcSquiggle.Width());
    RGBAImage image(width, 3, 1.0, 0);
    enum { alphaFull = 0xff, alphaSide = 0x2f, alphaSide2=0x5f };
    for (int x = 0; x < width; x++) {
        if (x%2) {
            // Two halfway columns have a full pixel in middle flanked by light pixels
            image.SetPixel(x, 0, fore, alphaSide);
            image.SetPixel(x, 1, fore, alphaFull);
            image.SetPixel(x, 2, fore, alphaSide);
        } else {
            // Extreme columns have a full pixel at bottom or top and a mid-tone pixel in centre
            image.SetPixel(x, (x%4) ? 0 : 2, fore, alphaFull);
            image.SetPixel(x, 1, fore, alphaSide2);
        }
    }
    surface->DrawRGBAImage(rcSquiggle, image.GetWidth(), image.GetHeight(), image.Pixels());
} else if (style == INDIC_SQUIGGLELOW) {
    surface->MoveTo(rc.left, rc.top);
    int x = rc.left + 3;
    int y = 0;
    while (x < rc.right) {
        surface->LineTo(x-1, rc.top + y);
        y = 1 - y;
        surface->LineTo(x, rc.top + y);
        x += 3;
    }
    surface->LineTo(rc.right, rc.top + y);  // Finish the line
} else if (style == INDIC_TT) {
    surface->MoveTo(rc.left, ymid);
    int x = rc.left + 5;
    while (x < rc.right) {
        surface->LineTo(x, ymid);
        surface->MoveTo(x-3, ymid);
        surface->LineTo(x-3, ymid+2);
        x++;
        surface->MoveTo(x, ymid);
        x += 5;
    }
    surface->LineTo(rc.right, ymid);    // Finish the line
    if (x - 3 <= rc.right) {
        surface->MoveTo(x-3, ymid);
        surface->LineTo(x-3, ymid+2);
    }
} else if (style == INDIC_DIAGONAL) {
    int x = rc.left;
    while (x < rc.right) {
        surface->MoveTo(x, rc.top+2);
        int endX = x+3;
        int endY = rc.top - 1;
        if (endX > rc.right) {
            endY += endX - rc.right;
            endX = rc.right;
        } 
                    surface->LineTo(endX, endY);
                    x += 4;
           }
    } else if (style == INDIC_STRIKE) {
            surface->MoveTo(rc.left, rc.top - 4);
            surface->LineTo(rc.right, rc.top - 4);
    } else if (style == INDIC_HIDDEN) {
            // Draw nothing
    } else if (style == INDIC_BOX) {
            surface->MoveTo(rc.left, ymid+1);
            surface->LineTo(rc.right, ymid+1);
            surface->LineTo(rc.right, rcLine.top+1);
            surface->LineTo(rc.left, rcLine.top+1);
            surface->LineTo(rc.left, ymid+1);
    } else if (style == INDIC_ROUNDBOX || style == INDIC_STRAIGHTBOX) {
            PRectangle rcBox = rcLine;
            rcBox.top = rcLine.top + 1;
            rcBox.left = rc.left;
            rcBox.right = rc.right;
            surface->AlphaRectangle(rcBox, (style == INDIC_ROUNDBOX) ? 1 : 0, fore, fillAlpha, fore, outlineAlpha, 0);
        } else if (style == INDIC_DOTBOX) {
            PRectangle rcBox = PixelGridAlign(rc);
            rcBox.top = rcLine.top + 1;
            rcBox.bottom = rcLine.bottom;
            // Cap width at 4000 to avoid large allocations when mistakes made
            int width = Platform::Minimum(rcBox.Width(), 4000);
            RGBAImage image(width, rcBox.Height(), 1.0, 0);
            // Draw horizontal lines top and bottom
            for (int x=0; x<width; x++) {
               for (int y=0; y<rcBox.Height(); y += rcBox.Height()-1) {
                    image.SetPixel(x, y, fore, ((x + y) % 2) ? outlineAlpha : fillAlpha);
                }
            }
            // Draw vertical lines left and right
            for (int y=1; y<rcBox.Height(); y++) {
                  for (int x=0; x<width; x += width-1) {
                       image.SetPixel(x, y, fore, ((x + y) % 2) ? outlineAlpha : fillAlpha);
                  }
             }
            surface->DrawRGBAImage(rcBox, image.GetWidth(), image.GetHeight(), image.Pixels());
           } else if (style == INDIC_DASH) {
           int x = rc.left;
           while (x < rc.right) {
                    surface->MoveTo(x, ymid);
                    surface->LineTo(Platform::Minimum(x + 4, rc.right), ymid);
                    x += 7; 
           }
       } else if (style == INDIC_DOTS) {
           int x = rc.left;
           while (x < rc.right) 
           {
                    PRectangle rcDot(x, ymid, x+1, ymid+1);
                    surface->FillRectangle(rcDot, fore);
                    x += 2;
             }
    } 
    else 
    {   // Either INDIC_PLAIN or unknown
    surface->MoveTo(rc.left, ymid);
    surface->LineTo(rc.right, ymid);
    }
 }

 ----------------------------------
 XPM.h

 # pragma once
 #include "Platform.h"
 #if defined(PLAT_QT)
 #include <qimage.h>
 #include <qpixmap.h>
 #endif

 #ifdef SCI_NAMESPACE
 namespace Scintilla {
 #endif

 /**
 * Hold a pixmap in XPM format.
 */
class XPM {
#if defined(PLAT_QT)
QPixmap qpm;

public:

XPM(const char *textForm);
XPM(const char *const *linesForm);
~XPM() {}

void Draw(Surface *surface, PRectangle &rc);
int GetHeight() const {return qpm.height();}

const QPixmap &Pixmap() const {return qpm;}
#else
int pid;        // Assigned by container
int height;
int width;
int nColours;
char *data;
char codeTransparent;
char *codes;
ColourDesired *colours;
ColourDesired ColourDesiredFromCode(int ch) const;
ColourDesired ColourFromCode(int ch) const;
void FillRun(Surface *surface, int code, int startX, int y, int x);
char **lines;
ColourDesired *colourCodeTable[256];

 public:
XPM(const char *textForm);
XPM(const char *const *linesForm);
~XPM();
void Init(const char *textForm);
void Init(const char *const *linesForm);
void Clear();
/// Decompose image into runs and use FillRectangle for each run
void Draw(Surface *surface, PRectangle &rc);
char **InLinesForm() { return lines; }
void SetId(int pid_) { pid = pid_; }
int GetId() const { return pid; }
int GetHeight() const { return height; }
int GetWidth() const { return width; }
void PixelAt(int x, int y, ColourDesired &colour, bool &transparent) const;
static const char **LinesFormFromTextForm(const char *textForm);
#endif
};

#if !defined(PLAT_QT)

/**
 * A collection of pixmaps indexed by integer id.
 */
class XPMSet {
XPM **set;  ///< The stored XPMs.
int len;    ///< Current number of XPMs.
int maximum;    ///< Current maximum number of XPMs, increased by steps if reached.
int height; ///< Memorize largest height of the set.
int width;  ///< Memorize largest width of the set.
 public:
XPMSet();
~XPMSet();
/// Remove all XPMs.
void Clear();
/// Add a XPM.
void Add(int ident, const char *textForm);
/// Get XPM by id.
XPM *Get(int ident);
/// Give the largest height of the set.
int GetHeight();
/// Give the largest width of the set.
int GetWidth();
 };

 #endif

 /**
  * An translucent image stoed as a sequence of RGBA bytes.
 */
class RGBAImage {
    // Private so RGBAImage objects can not be copied
    RGBAImage(const RGBAImage &);
    RGBAImage &operator=(const RGBAImage &);
    int height;
    int width;
    float scale;
   #if defined(PLAT_QT)
      QImage *qim;
    #else
    std::vector<unsigned char> pixelBytes;
   #endif
 public:
    //   RGBAImage has been defined here, why still linker error ??? 
    RGBAImage(int width_, int height_, float scale_, unsigned char const *pixels_);
    RGBAImage(const XPM &xpm);
    virtual ~RGBAImage();
    int GetHeight() const { return height; }
    int GetWidth() const { return width; }
    float GetScale() const { return scale; }
    float GetScaledHeight() const { return height / scale; }
    float GetScaledWidth() const { return width / scale; }
#if !defined(PLAT_QT)
    int CountBytes() const;
#endif
    const unsigned char *Pixels() const;
    //  SetPixel has been defined here, why still linker error ??? 
   void SetPixel(int x, int y, ColourDesired colour, int alpha=0xff); 
};

#if !defined(PLAT_QT)

 /**
 * A collection of RGBAImage pixmaps indexed by integer id.
 */
class RGBAImageSet {
    typedef std::map<int, RGBAImage*> ImageMap;
    ImageMap images;
    mutable int height; ///< Memorize largest height of the set.
    mutable int width;  ///< Memorize largest width of the set.
public:
     RGBAImageSet();
    ~RGBAImageSet();
   /// Remove all images.
   void Clear();
   /// Add an image.
   void Add(int ident, RGBAImage *image);
   /// Get image by id.
  RGBAImage *Get(int ident);
   /// Give the largest height of the set.
   int GetHeight() const;
   /// Give the largest width of the set.
   int GetWidth() const;
  };
 #endif    
 #ifdef SCI_NAMESPACE
 }

#endif

我再次解压了 tar ball，找到了 XMP.cpp 并运行 qmake (4.8.3) qscintilla.proa 并得到了 Makefile。但是我遇到了很多编译错误。例如
Qsci/qsciscintilla.h:34:21: 错误:qobject.h: 没有这样的文件或目录。我已经更新了我的帖子。

   [~/qscintilla2/QScintilla-gpl-2.7.1_new/QScintilla-gpl-2.7.1/Qt4Qt5] $ make
   g++ -c -pipe -O2 -D_REENTRANT -w -fPIC -DQSCINTILLA_MAKE_DLL -DQT -DSCI_LEXER -  DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -I../../../../qt483/qt-everywhere-opensource-src- 4.8.3/mkspecs/linux-g++ -I. -I/home/user//qt483/include/QtCore - I/home/user/qt483/include/QtGui -I/home/user/qt483/include -I. -I../include - I../lexlib -I../src -I. -o qsciscintilla.o qsciscintilla.cpp
   In file included from qsciscintilla.cpp:28:
  Qsci/qsciscintilla.h:34:21: error: qobject.h: No such file or directory
  Qsci/qsciscintilla.h:35:25: error: qstringlist.h: No such file or directory
  Qsci/qsciscintilla.h:37:22: error: QByteArray: No such file or directory
  Qsci/qsciscintilla.h:38:17: error: QList: No such file or directory
  Qsci/qsciscintilla.h:39:20: error: QPointer: No such file or directory
  In file included from Qsci/qsciscintilla.h:41,
              from qsciscintilla.cpp:28:
  ./Qsci/qsciglobal.h:33:21: error: qglobal.h: No such file or directory
  In file included from Qsci/qsciscintilla.h:42,
              from qsciscintilla.cpp:28:
  ./Qsci/qscicommand.h:33:21: error: qstring.h: No such file or directory
  In file included from ./Qsci/qscicommand.h:36,
               from Qsci/qsciscintilla.h:42,
             from qsciscintilla.cpp:28:
  ./Qsci/qsciscintillabase.h:35:31: error: QAbstractScrollArea: No such file or directory
  ./Qsci/qsciscintillabase.h:37:20: error: qpoint.h: No such file or directory
  ./Qsci/qsciscintillabase.h:38:20: error: qtimer.h: No such file or directory
    qsciscintilla.cpp:31:21: error: qaction.h: No such file or directory
    qsciscintilla.cpp:32:26: error: qapplication.h: No such file or directory
   qsciscintilla.cpp:33:20: error: qcolor.h: No such file or directory
   qsciscintilla.cpp:34:20: error: qevent.h: No such file or directory
   qsciscintilla.cpp:35:20: error: qimage.h: No such file or directory
   qsciscintilla.cpp:36:23: error: qiodevice.h: No such file or directory
   qsciscintilla.cpp:37:26: error: qkeysequence.h: No such file or directory
   qsciscintilla.cpp:40:19: error: qmenu.h: No such file or directory

  In file included from qsciscintilla.cpp:44:
   Qsci/qscilexer.h:34:19: error: qfont.h: No such file or directory
   Qsci/qscilexer.h:35:18: error: qmap.h: No such file or directory
  In file included from ./Qsci/qscicommand.h:36,
             from Qsci/qsciscintilla.h:42,
             from qsciscintilla.cpp:28:
  ./Qsci/qsciscintillabase.h:69: error: expected class-name before '{' token
  ./Qsci/qsciscintillabase.h:70: error: ISO C++ forbids declaration of 'Q_OBJECT' with  no type
  ./Qsci/qsciscintillabase.h:72: error: expected ';' before 'public'
  ./Qsci/qsciscintillabase.h:3011: error: expected ')' before '*' token

---

更新 Makefile 的 lib 路径并按照 QScintilla-gpl-2.7.1/doc/html-Qt4Qt5/index.html 上的安装说明进行操作后，我编译并安装了 QScintilla-gpl-2.7.1，没有错误。

但是，当我运行 example-Qt4Qt5/application 时出现了新的错误:

  ~/qscintilla2/QScintilla-gpl-2.7.1_new/QScintilla-gpl-2.7.1/example-Qt4Qt5] $   ./application

 Unable to load library icui18n "Cannot load library icui18n: (icui18n: cannot open shared object file: No such file or directory)"

Answer 1

The definition of class RGBAImage in src/XPM.h.

链接器不是在提示类的定义，而是在提示 XPM.cpp 中定义的类成员函数的定义

那应该在压缩包里，所以你一定是在提取代码的时候做错了什么。