c++ - 包含GetPot

我面临GetPot(http://getpot.sourceforge.net/)的问题，即当我多次包含它时，链接器会出现multiple definition错误。

这是MWE:

文件main.cpp:

#include "GetPot"

int main()
{
    return 0;
}

文件foo.cpp:

#include "GetPot"

void foo()
{
    GetPot configurationFileParser("foobar");
    double bar = configurationFileParser("bar", 0.0);
}

(所有GetPot文件GetPot，GetPot.hpp和GetPot.cpp与main.cpp和foo.cpp都位于同一目录中)。

用g++ main.cpp foo.cpp编译，我得到:

/tmp/ccD22ma0.o: In function `GetPot::__constraint_check(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*, bool) const':
foo.cpp:(.text+0x0): multiple definition of `GetPot::__constraint_check(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*, bool) const'
/tmp/ccxM8JHn.o:main.cpp:(.text+0x0): first defined here
/tmp/ccD22ma0.o: In function `GetPot::__constraint_check_OR(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const':
foo.cpp:(.text+0x5ca): multiple definition of `GetPot::__constraint_check_OR(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const'
/tmp/ccxM8JHn.o:main.cpp:(.text+0x5ca): first defined here
/tmp/ccD22ma0.o: In function `GetPot::__constraint_check_AND(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const':
foo.cpp:(.text+0x752): multiple definition of `GetPot::__constraint_check_AND(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const'
/tmp/ccxM8JHn.o:main.cpp:(.text+0x752): first defined here
/tmp/ccD22ma0.o: In function `GetPot::__constrain_check_EQUAL_STRING(char const*, char const**) const':
foo.cpp:(.text+0x692): multiple definition of `GetPot::__constrain_check_EQUAL_STRING(char const*, char const**) const'
/tmp/ccxM8JHn.o:main.cpp:(.text+0x692): first defined here
/tmp/ccD22ma0.o: In function `GetPot::__constraint_check_PRIMARY(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const':
foo.cpp:(.text+0x81e): multiple definition of `GetPot::__constraint_check_PRIMARY(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const**) const'
/tmp/ccxM8JHn.o:main.cpp:(.text+0x81e): first defined here
collect2: error: ld returned 1 exit status
(ins)mattia@endor:getpot-c++$

另一方面，将GetPot.cpp编译为目标文件GetPot.o，然后仅在源文件中包含GetPot.hpp也不起作用，因为GetPot::operator()仅在GetPot.cpp中声明，因此出现错误:

/tmp/ccSIAz1V.o: In function `foo()':
foo.cpp:(.text+0x106): undefined reference to `double GetPot::operator()<double>(StringOrCharP, double) const'
collect2: error: ld returned 1 exit status
(ins)mattia@endor:getpot-c++$

无论如何，这整个问题使我感到困惑，因为GetPot.hpp和GetPot.cpp都包含防护，因此不应首先出现多个定义。

我究竟做错了什么？真的没有办法在文件集合中多次包含GetPot吗(特别是例如在编写库时)？

非常感谢你

马蒂亚

最佳答案

GetPot仅应包含在一个文件中。否则，您可以考虑遍历成员函数并使之内联而不是内联。