尝试扩展ctype构面时未定义的引用错误

我试图通过扩展ctype <uint32_t>来创建自定义ctype构面，但不断收到未定义的引用错误。尝试扩展ctype构面时未定义的引用错误

下面是一个最小的测试程序重现错误：

#include <locale> 

using namespace std; 

class my_ctype : public ctype<uint32_t> { 
public: 
    explicit my_ctype(size_t __refs = 0); 

protected: 
    virtual ~my_ctype(); 

protected: 
    virtual bool do_is(mask __m, char_type __c) const; 
    virtual const char_type* do_is(const char_type* __lo, const char_type* __hi, mask* __vec) const; 
    virtual const char_type* do_scan_is(mask __m, const char_type* __lo, const char_type* __hi) const; 
    virtual const char_type* do_scan_not(mask __m, const char_type* __lo, const char_type* __hi) const; 
    virtual char_type do_toupper(char_type __c) const; 
    virtual const char_type* do_toupper(char_type* __lo, const char_type* __hi) const; 
    virtual char_type do_tolower(char_type __c) const; 
    virtual const char_type* do_tolower(char_type* __lo, const char_type* __hi) const; 
    virtual char_type do_widen(char __c) const; 
    virtual const char* do_widen(const char* __lo, const char* __hi, char_type* __dest) const; 
    virtual char do_narrow(char_type __c, char __dfault) const; 
    virtual const char_type* do_narrow(const char_type* __lo, const char_type* __hi, char __dfault, char* __to) const; 
}; 

my_ctype::my_ctype(size_t __refs) : ctype<uint32_t>(__refs) {} 

my_ctype::~my_ctype() {} 

bool my_ctype::do_is(mask __m, char_type __c) const { return false; } 
const my_ctype::char_type* my_ctype::do_is(const char_type* __lo, const char_type* __hi, mask* __vec) const { return __hi; } 
const my_ctype::char_type* my_ctype::do_scan_is(mask __m, const char_type* __lo, const char_type* __hi) const { return __hi; } 
const my_ctype::char_type* my_ctype::do_scan_not(mask __m, const char_type* __lo, const char_type* __hi) const { return __hi; } 
my_ctype::char_type my_ctype::do_toupper(char_type __c) const { return __c; } 
const my_ctype::char_type* my_ctype::do_toupper(char_type* __lo, const char_type* __hi) const { return __hi; } 
my_ctype::char_type my_ctype::do_tolower(char_type __c) const { return __c; } 
const my_ctype::char_type* my_ctype::do_tolower(char_type* __lo, const char_type* __hi) const { return __hi; } 
my_ctype::char_type my_ctype::do_widen(char __c) const { return __c; } 
const char* my_ctype::do_widen(const char* __lo, const char* __hi, char_type* __dest) const { return __hi; } 
char my_ctype::do_narrow(char_type __c, char __dfault) const { return __dfault; } 
const my_ctype::char_type* my_ctype::do_narrow(const char_type* __lo, const char_type* __hi, char __dfault, char* __to) const { return __hi; } 



int main() { 
    my_ctype* c = new my_ctype(); 

    return 0; 
}

，这里是错误我越来越：

Linking console executable: bin\Debug\ctype.exe 
obj\Debug\main.o: In function `_ZN8my_ctypeD2Ev': 
D:/[...]/ctype/main.cpp:29: undefined reference to `std::ctype<unsigned int>::~ctype()' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x8): undefined reference to `std::ctype<unsigned int>::~ctype()' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0xc): undefined reference to `std::ctype<unsigned int>::~ctype()' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x10): undefined reference to `std::ctype<unsigned int>::do_is(unsigned short, unsigned int) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x14): undefined reference to `std::ctype<unsigned int>::do_is(unsigned int const*, unsigned int const*, unsigned short*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x18): undefined reference to `std::ctype<unsigned int>::do_scan_is(unsigned short, unsigned int const*, unsigned int const*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x1c): undefined reference to `std::ctype<unsigned int>::do_scan_not(unsigned short, unsigned int const*, unsigned int const*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x20): undefined reference to `std::ctype<unsigned int>::do_toupper(unsigned int) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x24): undefined reference to `std::ctype<unsigned int>::do_toupper(unsigned int*, unsigned int const*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x28): undefined reference to `std::ctype<unsigned int>::do_tolower(unsigned int) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x2c): undefined reference to `std::ctype<unsigned int>::do_tolower(unsigned int*, unsigned int const*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x30): undefined reference to `std::ctype<unsigned int>::do_widen(char) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x34): undefined reference to `std::ctype<unsigned int>::do_widen(char const*, char const*, unsigned int*) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x38): undefined reference to `std::ctype<unsigned int>::do_narrow(unsigned int, char) const' 
obj\Debug\main.o:main.cpp:(.rdata$_ZTVSt5ctypeIjE[vtable for std::ctype<unsigned int>]+0x3c): undefined reference to `std::ctype<unsigned int>::do_narrow(unsigned int const*, unsigned int const*, char, char*) const' 
collect2.exe: error: ld returned 1 exit status 
Process terminated with status 1 (0 minutes, 1 seconds) 
15 errors, 1 warnings

我看着locale_facets.h，并发现有ctype的模板专门化<char>和ctype <wchar_t>，恐怕我可能不得不为uint32_t创建专门化，但我只是不明白为什么。

因此，这里是我的问题：

1 - 为什么我收到这些错误消息？

2 - 我该如何解决？

3 - 如果我确实需要为uint32_t专门设置ctype < >，为什么会出现这种情况？

我正在使用mingw在windows上编译我的程序，通过CodeBlocks。测试程序只有main.cpp，没有其他文件。

来源

2012-08-09 akamaru

'std :: ctype'用于字符，你想要做什么？ – 2012-08-10 00:00:22

@JesseGood我试图为unicode字符实现它。 – akamaru 2012-08-10 00:35:36

由于没有专业化的uint32_t的
写一个专业化
基类必须实现

考虑下面

class A { public: virtual void func(); // no implementation here virtual ~A(); }; class B : public A { public: virtual void func() {} };

实例代码的B无法创建。

来源

2012-08-10 00:02:20 silvesthu

我想我知道了......类ctype <>中定义的方法既没有实现，也没有定义为纯虚拟，因此编译器希望在另一个源文件的某处找到它们的实现，这种情况不会发生。所以唯一的解决方案是为类ctype <>本身提供这些实现，而不仅仅是派生类。这意味着专门化ctype <>。 – akamaru 2012-08-10 00:46:44

是的。仅供参考，即使所有函数都被标记为纯虚函数，但仍需要实现基类中的析构函数。 http://stackoverflow.com/questions/1219607/why-do-we-need-a-pure-virtual-destructor-in-c – silvesthu 2012-08-10 00:58:25

我的问题是没有构造函数，希望能帮助别人！

来源

2013-05-15 02:02:14 jp093121

尝试扩展ctype构面时未定义的引用错误

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