Question

这是我的第一个问题，请耐心等待。

我需要以头文件和.so文件的形式向我的qt项目添加一个外部库。如果仅在main.cpp中包含头文件（figure.h），则程序将按预期进行编译和运行。如果仅将头文件包含在scene.cpp中，则程序将再次编译。但是，当我将头文件添加到scene.h时，编译器会指出存在重复的符号，即使该头文件未包含在项目中的其他位置也是如此。有没有人可以帮忙？这让我难过了一段时间。

.pro文件：

    QT       += core gui widgets

    greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

    TARGET = moebinv-gui
    TEMPLATE = app

    INCLUDEPATH += /usr/local/include $$PWD/include
    DEPENDPATH += /usr/local/include $$PWD/include

    QMAKE_LFLAGS += -v

    unix: LIBS += -L/usr/local/lib/ -lginac -lcycle -lfigure

    SOURCES += \
            src/main.cpp \
            src/mainwindow.cpp \
            src/scene.cpp

    HEADERS += \
            include/mainwindow.h \
            include/scene.h

scene.h：

#ifndef SCENE_H
#define SCENE_H

#include <QGraphicsScene>
#include <figure.h>

class graphicsScene : public QGraphicsScene
{
    Q_OBJECT

private:
    MoebInv::figure *f;

};

#endif // SCENE_H

编译器错误：

duplicate symbol __ZN7MoebInv11default_asyE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv17evaluation_assistE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv8metric_pE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv13default_labelE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv8metric_hE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv8metric_eE in:
    main.o
    mainwindow.o
duplicate symbol __ZN7MoebInv11default_asyE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv17evaluation_assistE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv8metric_pE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv13default_labelE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv8metric_hE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv8metric_eE in:
    main.o
    scene.o
duplicate symbol __ZN7MoebInv11default_asyE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv17evaluation_assistE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv8metric_pE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv13default_labelE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv8metric_hE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv8metric_eE in:
    main.o
    moc_mainwindow.o
duplicate symbol __ZN7MoebInv11default_asyE in:
    main.o
    moc_scene.o
duplicate symbol __ZN7MoebInv17evaluation_assistE in:
    main.o
    moc_scene.o
duplicate symbol __ZN7MoebInv8metric_pE in:
    main.o
    moc_scene.o
duplicate symbol __ZN7MoebInv13default_labelE in:
    main.o
    moc_scene.o
duplicate symbol __ZN7MoebInv8metric_hE in:
    main.o
    moc_scene.o
duplicate symbol __ZN7MoebInv8metric_eE in:
    main.o
    moc_scene.o
ld: 24 duplicate symbols for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [moebinv-gui.app/Contents/MacOS/moebinv-gui] Error 1
12:08:20: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project moebinv-gui (kit: Desktop Qt 5.11.1 clang 64bit)
When executing step "Make"

Answer 1

您不能在头文件中定义全局变量。例如，您有：

asy_style default_asy=asy_cycle_color;

您必须在标头中将变量声明为extern：

extern asy_style default_asy;

然后在一个cpp文件中定义它：

asy_style default_asy=asy_cycle_color;

或者如果全局实际上是一个常量，则可以在标头中定义它：

const asy_style default_asy=asy_cycle_color;

Qt外部库重复符号链接错误

1 个答案: