将 D 库链接到 C++ 代码答案

【问题标题】：Linking D library to C++ code将 D 库链接到 C++ 代码
【发布时间】：2013-07-12 11:03:51
【问题描述】：

最近我学习了优美的语言 D，它更易塑化，可以帮助你编写稳定快速的程序。但它并不流行……因为很少有代码写在 D 上，而更多的是写在 C 和 C++ 上。因此，在我阅读了 Andrei Alexanderscu 的书后，作者非常肤浅地描述了关于将 D 库链接到 C++ 代码的问题，我尝试自己学习并在 D 上编写了一些代码，其中定义的函数返回一个 CompleteAutomata 类的实例，该实例也定义了 AutomataInterface在 C++ 代码中：

#ifndef AUTOMATAINTERFACE_H
#define AUTOMATAINTERFACE_H

class AutomataInterface {
public:
    virtual ~AutomataInterface() {}

    virtual void next() = 0;

    virtual void save() = 0;
    virtual void restore() = 0;
    virtual void zerofile() = 0;

    virtual void invert(unsigned long x, unsigned long y) = 0;

    virtual int state(unsigned long x, unsigned long y) const = 0;

    virtual unsigned long x() const = 0;
    virtual unsigned long y() const = 0;
};

AutomataInterface *createAutomata(unsigned long x, unsigned long y);

#endif // AUTOMATAINTERFACE_H

相关D码：

import agregator; // this is my own lib

extern(C++) {
    interface AutomataInterface {
        void next();

        void save();
        void restore();
        void zerofile();

        void invert(size_t x, size_t y);

        int state(size_t x, size_t y) const;

        size_t x() const;
        size_t y() const;
    }

    AutomataInterface createAutomata(ulong x, ulong y) {
        return new CompleteAutomata(x, y);
    }
}

export class CompleteAutomata : AutomataInterface {
    // instance variables...
    this(size_t x, size_t y) { /* ... */ }

    extern(C++) {
        override void next() {
            // ...
        }

        // others overridden interface methods...
    }
}

代码编写完成后，我通过两个不同的编译器（dmd 和 gdc）编译了 D 库，带有以下标志：

dmd -release -O -lib -odlib -ofliblife.h *.d

或

gdc -frelease -O2 -Wall -c *.d
ar cq lib/liblife.a *.o

当我尝试通过添加库目录的路径（-L 选项）并直接添加一个库（-l 选项）将每个收到的库链接到 Qt 项目时。在这两种情况下我都有错误。

在第一个 dmd 案例中，我有“未定义的对 `_d_newclass' 的引用”以及另外几个错误：

g++ -Wl,-O1 -Wl,-z,relro -o automata main.o mainwindow.o renderarea.o button.o playbutton.o moc_mainwindow.o moc_renderarea.o moc_button.o moc_playbutton.o -L/home/newmen/projects/d/life/lib -llife -lQtGui -lQtCore -lpthread 
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1fe_5b0.o): In function `createAutomata(unsigned int, unsigned int)':
complete_automata.d:(.text._Z14createAutomatajj+0x27): undefined reference to `_d_newclass'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0x0): undefined reference to `_D14TypeInfo_Class6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0x50): undefined reference to `_D6Object7__ClassZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0xd0): undefined reference to `_D14TypeInfo_Class6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0x120): undefined reference to `_D6Object7__ClassZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x68): undefined reference to `_D6object6Object8toStringMFZAya'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x70): undefined reference to `_D6object6Object6toHashMFNbNeZm'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x78): undefined reference to `_D6object6Object5opCmpMFC6ObjectZi'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x80): undefined reference to `_D6object6Object8opEqualsMFC6ObjectZb'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0xf8): undefined reference to `_D6object6Object8toStringMFZAya'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x100): undefined reference to `_D6object6Object6toHashMFNbNeZm'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x108): undefined reference to `_D6object6Object5opCmpMFC6ObjectZi'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x110): undefined reference to `_D6object6Object8opEqualsMFC6ObjectZb'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o): In function `_D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata':
complete_automata.d:(.text._D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata+0x1f): undefined reference to `_d_newclass'
complete_automata.d:(.text._D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata+0x46): undefined reference to `_d_newclass'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o): In function `CompleteAutomata::next()':
complete_automata.d:(.text._ZN16CompleteAutomata4nextEv+0x2f): undefined reference to `_d_newclass'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o): In function `CompleteAutomata::save()':
complete_automata.d:(.text._ZN16CompleteAutomata4saveEv+0x25): undefined reference to `_adDupT'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o): In function `CompleteAutomata::restore()':
complete_automata.d:(.text._ZN16CompleteAutomata7restoreEv+0x33): undefined reference to `_d_newclass'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o): In function `CompleteAutomata::zerofile()':
complete_automata.d:(.text._ZN16CompleteAutomata8zerofileEv+0x2f): undefined reference to `_d_newclass'
/home/newmen/projects/d/life/lib/liblife.a(object_201_8b7.o): In function `no symbol':
/usr/include/dmd/druntime/import/object.di:(.text+0x6): undefined reference to `_Dmodule_ref'
/home/newmen/projects/d/life/lib/liblife.a(object_201_8b7.o):(.data._D12TypeInfo_Axi6__initZ+0x0): undefined reference to `_D14TypeInfo_Array6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(object_201_8b7.o): In function `_D46/usr/include/dmd/druntime/import/object.di.5137__arrayZ':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.5137__arrayZ+0x16): undefined reference to `_d_array_bounds'
/home/newmen/projects/d/life/lib/liblife.a(object_201_8b7.o): In function `_D46/usr/include/dmd/druntime/import/object.di.5138__assertFiZv':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.5138__assertFiZv+0x16): undefined reference to `_d_assertm'
/home/newmen/projects/d/life/lib/liblife.a(object_201_8b7.o): In function `_D46/usr/include/dmd/druntime/import/object.di.51315__unittest_failFiZv':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.51315__unittest_failFiZv+0x16): undefined reference to `_d_unittestm'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o): In function `no symbol':
/usr/include/dmd/druntime/import/object.di:(.text+0x6): undefined reference to `_Dmodule_ref'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o):(.data._D11TypeInfo_xi6__initZ+0x0): undefined reference to `_D14TypeInfo_Const6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o):(.data._D11TypeInfo_xi6__initZ+0x10): undefined reference to `_D10TypeInfo_i6__initZ'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o): In function `_D46/usr/include/dmd/druntime/import/object.di.5157__arrayZ':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.5157__arrayZ+0x16): undefined reference to `_d_array_bounds'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o): In function `_D46/usr/include/dmd/druntime/import/object.di.5158__assertFiZv':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.5158__assertFiZv+0x16): undefined reference to `_d_assertm'
/home/newmen/projects/d/life/lib/liblife.a(object_203_875.o): In function `_D46/usr/include/dmd/druntime/import/object.di.51515__unittest_failFiZv':
/usr/include/dmd/druntime/import/object.di:(.text._D46/usr/include/dmd/druntime/import/object.di.51515__unittest_failFiZv+0x16): undefined reference to `_d_unittestm'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `no symbol':
agregator.d:(.text+0x6): undefined reference to `_Dmodule_ref'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o):(.data+0x10): undefined reference to `_D3std6random12__ModuleInfoZ'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o):(.rodata+0x20): undefined reference to `_D14TypeInfo_Class6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D9agregator7__arrayZ':
agregator.d:(.text._D9agregator7__arrayZ+0x16): undefined reference to `_d_array_bounds'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D9agregator8__assertFiZv':
agregator.d:(.text._D9agregator8__assertFiZv+0x16): undefined reference to `_d_assertm'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D9agregator15__unittest_failFiZv':
agregator.d:(.text._D9agregator15__unittest_failFiZv+0x16): undefined reference to `_d_unittestm'
/home/newmen/projects/d/life/lib/liblife.a(agregator_2_5fd.o):(.data+0x0): undefined reference to `_D14TypeInfo_Class6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(agregator_2_5fd.o):(.data+0x50): undefined reference to `_D6Object7__ClassZ'
/home/newmen/projects/d/life/lib/liblife.a(agregator_2_5fd.o):(.rodata+0x48): undefined reference to `_D6object6Object8toStringMFZAya'
...

在第二种情况下（使用gdc）我收到有关“多重定义”的消息：

g++ -Wl,-O1 -Wl,-z,relro -o cellular_life main.o mainwindow.o renderarea.o button.o playbutton.o moc_mainwindow.o moc_renderarea.o moc_button.o moc_playbutton.o -L/home/newmen/projects/d/life/lib -llife -lQtGui -lQtCore -lpthread 
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `_D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi':
complete_automata.d:(.text+0x0): multiple definition of `_D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::invert(unsigned long long, unsigned long long)':
complete_automata.d:(.text+0x40): multiple definition of `CompleteAutomata::invert(unsigned long long, unsigned long long)'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZN16CompleteAutomata6invertEyy+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::state(unsigned long long, unsigned long long) const':
complete_automata.d:(.text+0x60): multiple definition of `CompleteAutomata::state(unsigned long long, unsigned long long) const'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZNK16CompleteAutomata5stateEyy+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::x() const':
complete_automata.d:(.text+0x80): multiple definition of `CompleteAutomata::x() const'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZNK16CompleteAutomata1xEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::y() const':
complete_automata.d:(.text+0xa0): multiple definition of `CompleteAutomata::y() const'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZNK16CompleteAutomata1yEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::next()':
complete_automata.d:(.text+0x140): multiple definition of `CompleteAutomata::next()'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZN16CompleteAutomata4nextEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.tbss+0x10): multiple definition of `_D17complete_automata16CompleteAutomata4nextMRZv7changerC7changer7Changer'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.tbss+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::restore()':
complete_automata.d:(.text+0x1b0): multiple definition of `CompleteAutomata::restore()'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZN16CompleteAutomata7restoreEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.tbss+0x8): multiple definition of `_D17complete_automata16CompleteAutomata7restoreMRZv9agregatorC9agregator9Agregator'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.tbss+0x8): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.data+0x180): multiple definition of `_D_ZN16CompleteAutomata7restoreEv14SliceAgregator7__ClassZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::zerofile()':
complete_automata.d:(.text+0x220): multiple definition of `CompleteAutomata::zerofile()'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZN16CompleteAutomata8zerofileEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.tbss+0x0): multiple definition of `_D17complete_automata16CompleteAutomata8zerofileMRZv9agregatorC9agregator9Agregator'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.tbss+0x10): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::save()':
complete_automata.d:(.text+0x290): multiple definition of `CompleteAutomata::save()'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._ZN16CompleteAutomata4saveEv+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.data+0x80): multiple definition of `_D17complete_automata16CompleteAutomata7__ClassZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.data+0xd0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `_D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata':
complete_automata.d:(.text+0x9b0): multiple definition of `_D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):complete_automata.d:(.text._D17complete_automata16CompleteAutomata6__ctorMFmmZC17complete_automata16CompleteAutomata+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.rodata+0x420): multiple definition of `_D17complete_automata16CompleteAutomata6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0xf0): first defined here
/usr/bin/ld: Warning: size of symbol `_D17complete_automata16CompleteAutomata6__vtblZ' changed from 104 in /home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o) to 112 in /home/newmen/projects/d/life/lib/liblife.a(complete_automata.o)
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.rodata+0x4a0): multiple definition of `_D17complete_automata16CompleteAutomata6__initZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x90): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.rodata+0x4e0): multiple definition of `_D_ZN16CompleteAutomata7restoreEv14SliceAgregator6__vtblZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x60): first defined here
/usr/bin/ld: Warning: size of symbol `_D_ZN16CompleteAutomata7restoreEv14SliceAgregator6__vtblZ' changed from 48 in /home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o) to 56 in /home/newmen/projects/d/life/lib/liblife.a(complete_automata.o)
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o):(.rodata+0x520): multiple definition of `_D_ZN16CompleteAutomata7restoreEv14SliceAgregator6__initZ'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1ff_675.o):(.rodata+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D3std7complex14__T7ComplexTeZ7Complex8toStringMxFMDFAxaZvAyaZAya12__lambda1223MFNbNfAxaZv':
agregator.d:(.text+0xaf): undefined reference to `_D11TypeInfo_Aa6__initZ'
agregator.d:(.text+0xb7): undefined reference to `_d_arrayappendT'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D3std4conv16__T6toImplTiTxkZ6toImplFNaNfxkZi15__dgliteral1389MFNaNfZC6object9Throwable':
agregator.d:(.text+0xc5): undefined reference to `_D3std4conv21ConvOverflowException7__ClassZ'
agregator.d:(.text+0xca): undefined reference to `_d_newclass'
agregator.d:(.text+0xed): undefined reference to `_D3std4conv21ConvOverflowException6__ctorMFAyaAyamZC3std4conv21ConvOverflowException'
/home/newmen/projects/d/life/lib/liblife.a(agregator.o): In function `_D3std6format17__T9getNthIntTxeZ9getNthIntFNaNfkxeZi.part.6':
agregator.d:(.text+0x105): undefined reference to `_D3std6format15FormatException7__ClassZ'
agregator.d:(.text+0x10a): undefined reference to `_d_newclass'
...

经过两天的尝试……

最近我尝试将 Phobos（D 标准库）添加到链接过程中。对于dmd -lphobos2 标志和gdc -lgphobos2 标志对应。但这对我没有帮助...

使用dmd链接器输出时：

g++ -Wl,-O1 -Wl,-z,relro -o cellular_life main.o mainwindow.o renderarea.o button.o playbutton.o moc_mainwindow.o moc_renderarea.o moc_button.o moc_playbutton.o -L/home/newmen/projects/d/life/lib -llife -lQtGui -lQtCore -lpthread -lphobos2
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_duphandle@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_strerror@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_slist_free_all@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_global_init@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_perform@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_init@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_pause@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `_Dmain'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_setopt@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_slist_append@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_global_cleanup@CURL_GNUTLS_3'
/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../lib64/libphobos2.so: undefined reference to `curl_easy_cleanup@CURL_GNUTLS_3'
collect2: error: ld returned 1 exit status
make: *** [cellular_life] Error 1

我已经尝试替代 libcurl-gnutls：ln -s /usr/lib64/libcurl.so.4 /usr/lib64/libcurl-gnutls.so.4。然后链接相同但没有关于 libcurl-gnutls 的消息的结果。

在使用gdc链接器输出时再谈“多重定义到”：

/home/newmen/gcc/bin/g++ -Wl,-O1 -Wl,-z,relro -o cellular_life main.o mainwindow.o renderarea.o button.o playbutton.o moc_mainwindow.o moc_renderarea.o moc_button.o moc_playbutton.o    -L/home/newmen/gcc/lib64 -L/home/newmen/projects/d/life/lib -llife -lQtGui -lQtCore -lpthread -lgphobos2
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `_D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi':
complete_automata.d:(.text+0x0): multiple definition of `_D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1e3_675.o):complete_automata.d:(.text._D17complete_automata16CompleteAutomata7restoreMRZv14SliceAgregator9initValueMxFmmZi+0x0): first defined here
/home/newmen/projects/d/life/lib/liblife.a(complete_automata.o): In function `CompleteAutomata::invert(unsigned long long, unsigned long long)':
complete_automata.d:(.text+0x40): multiple definition of `CompleteAutomata::invert(unsigned long long, unsigned long long)'
/home/newmen/projects/d/life/lib/liblife.a(complete_automata_1e3_675.o):complete_automata.d:(.text._ZN16CompleteAutomata6invertEyy+0x0): first defined here
...
/home/newmen/gcc/lib64/libgphobos2.a(dmain2.o): In function `main':
/home/newmen/projects/distrib/gcc-4.8.1/x86_64-unknown-linux-gnu/libphobos/libdruntime/../../.././libphobos/libdruntime/rt/dmain2.d:394: multiple definition of `main'
main.o:/home/newmen/projects/d/life/qt_viewer/main.cpp:5: first defined here
/usr/bin/ld: /home/newmen/gcc/lib64/libgphobos2.a(time.o): undefined reference to symbol 'clock_getres@@GLIBC_2.2.5'
/usr/bin/ld: note: 'clock_getres@@GLIBC_2.2.5' is defined in DSO /lib64/librt.so.1 so try adding it to the linker command line
/lib64/librt.so.1: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status
make: *** [cellular_life] Error 1

最后有关于 librt.so.1 的消息。我检查 /usr/lib64 并在那里看到它的库文件。

亲爱的魔术师，请告诉我如何将 D 库连接到 C++ 代码。

【问题讨论】：

标签： c++ d undefined-reference multiple-definition-error

【解决方案1】：

让 D 编译器进行链接通常更容易：

 g++ -c yourfile.cpp
 dmd yourfile.o d_file.d

您可能还需要向它添加 curl，就像以前一样。要通过 dmd 传递链接器参数（如果使用 gdc，则为 gdmd，应该以相同的方式工作），传递 -Larg

 dmd yourfile.o d_file.d -L-lstdc++ -L-lcurl -L-lQtGui # and so on

通常将 main() 放入 D 中也更容易（它也可以立即调用 C++ 定义的函数），因为否则您可能必须在从 C++ 中使用 D 运行时之前对其进行初始化。

但是要完成您已经开始的过程...首先，您的 liblife.a 似乎已将相同的文件添加了两次。我会尝试删除该文件并重新创建它，或者只是跳过该步骤并将 .o 文件直接传递给链接器，而无需先将它们打包到 .a 中。这会简化一些事情。

我的另一个问题是：它为什么要拉 D 主线？您的 .d 代码中是否有 main() ？如果是这样，那没关系，但是您必须从 C++ 代码中删除它。（也许将其重命名为 cppmain ，然后从 D main 调用它：

D 码：

extern(C++) int cppmain(int argc, char** argv);

int main() {
        import core.runtime;
        return cppmain(Runtime.cArgs.argc, Runtime.cArgs.argv);
}

这将转发到您的 C++ 主程序。如果您想删除 D main（假设它在那里，如果不让我知道，我会尝试考虑还有什么可能导致该链接器错误），在您在 C++ 中使用 D 代码之前，您需要初始化 D . 所以：

D 码：

extern(C++) void initD() {
      import core.runtime;
       Runtime.initialize();
}

C++ 代码：

extern "C++" void initD();
int main() {
      initD();
      // the rest of your stuff
 }

如果不这样做，调用 D 函数可能会导致段错误。

但总而言之，我很确定您在存档中添加了一个重复的 .o 文件，并且 main 用 D 和 C++ 定义。删除存档中的重复项并杀死其中一个重复的主干线，您应该会取得一些成功。

【讨论】：

在看到你的答案之前，我发现作为链接器需要使用dmd。我尝试在 C++ 代码中描述的 main 函数时链接代码。在这种情况下，我得到了二进制文件，并且在启动时出现了段错误，您会对此发出警告。现在，在阅读了您的帖子后，我尝试在 D 代码中创建一个 main 函数并从它调用 cppmain 函数，正如您所写的那样。在这种情况下，链接后我也得到了二进制文件，这也是开始出现段错误的时候，但是这次回溯更加丰富，这表明在引用D类CompleteAutomata的方法时发生了错误
从 C++ 到 D 的一个常见错误是 D 类总是需要在堆上分配，因此请确保您正在执行：CompleteAutomata a = new CompleteAtomata();，而不仅仅是 CompleteAutomata a ;.原因是 D 中的类总是通过引用来完成的（D 中的 MyClass a 最像 C++ 中的 MyClass* a），所以如果你不使用 new 对其进行初始化，那么在使用时引用将是 null 和 segfault。
另一个注意事项，D 类应该是从 D 中新建的，而 C++ 类应该用 C++ 构造。有一种方法可以解决这个问题，但是这些语言不知道如何调用彼此的构造函数，因此您必须手动进行初始化对象。不过，用他们的母语来更新它要容易得多。
我使用 createAutomata 函数来创建一个 CompleteAutomata 对象，正如我在我的帖子（new）中所描述的那样。它在 C++ 中声明并在 D 中实现。在 C++ 代码中调用此函数，并将结果分配给指向 AutomataInterface 的指针。此外，试图通过这个指针调用一个类的方法会导致setfault。
我下载了您的代码，并且能够链接并运行它。如果您仍然无法链接，请告诉我，我也会写下来。但是我在您的 C++ 代码中发现了两个问题： 1) automatainterface.h 列出了一个虚拟析构函数——它不应该存在，所以只需将其注释掉。这就是导致段错误的原因，C++ 和 D 没有就虚函数的数量达成一致，所以一切都错了。第二个错误是在 ~RenderArea 中，你“删除了 _cellular”——不要这样做，因为它是在 D 中创建的，所以 D 垃圾收集器管理它。手动删除会造成双重释放。