来自yaml-cpp的编译器错误

Question

我正试图将yaml-cpp整合到一个项目中，但我看到GCC犯了一些意想不到的错误。例如：

g++ -c -ggdb3 -ansi -Wall -Werror -pedantic-errors src/commands-tz.cpp -o obj/commands-tz.o
In file included from /usr/local/include/yaml-cpp/conversion.h:9,
                 from /usr/local/include/yaml-cpp/node.h:8,
                 from /usr/local/include/yaml-cpp/parser.h:8,
                 from /usr/local/include/yaml-cpp/yaml.h:8,
                 from src/note.h:26,
                 from src/commands-tz.cpp:297:
/usr/local/include/yaml-cpp/traits.h:26: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:26: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:26: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:26: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/traits.h:31: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:31: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:31: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:31: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/traits.h:34: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:34: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:34: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:34: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/traits.h:37: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:37: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:37: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:37: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/traits.h:42: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:42: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:42: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:42: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/traits.h:45: error: expected identifier before ‘(’ token
/usr/local/include/yaml-cpp/traits.h:45: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:45: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/traits.h:45: error: expected unqualified-id before ‘)’ token

另一个例子是：

In file included from /usr/local/include/yaml-cpp/nodeimpl.h:8,
                 from /usr/local/include/yaml-cpp/node.h:139,
                 from /usr/local/include/yaml-cpp/parser.h:8,
                 from /usr/local/include/yaml-cpp/yaml.h:8,
                 from src/note.h:26,
                 from src/commands-tz.cpp:297:
/usr/local/include/yaml-cpp/nodeutil.h:9: error: expected nested-name-specifier before ‘(’ token
/usr/local/include/yaml-cpp/nodeutil.h:9: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:9: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:9: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/nodeutil.h:14: error: expected nested-name-specifier before ‘(’ token
/usr/local/include/yaml-cpp/nodeutil.h:14: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:14: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:14: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/nodeutil.h:19: error: expected nested-name-specifier before ‘(’ token
/usr/local/include/yaml-cpp/nodeutil.h:19: error: expected ‘)’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:19: error: expected ‘>’ before numeric constant
/usr/local/include/yaml-cpp/nodeutil.h:19: error: expected unqualified-id before ‘)’ token
/usr/local/include/yaml-cpp/nodeutil.h:24: error: ‘is_index_type_with_check’ is not a template
/usr/local/include/yaml-cpp/nodeutil.h:24: error: explicit specialization of non-template ‘YAML::is_index_type_with_check’

我的平台是Fedora (2.6.32内核)，GCC 4.4.1和yaml-cpp 0.2.5.还有很多很多其他的错误。在肉眼看来，这似乎是yaml-cpp的一个问题，但经验告诉我，可能是我的错。有什么想法吗？

更新

H文件包含以下内容：

namespace YAML
{
        template <typename>
        struct is_numeric { enum { value = false }; };

        template <> struct is_numeric <char> { enum { value = true }; };
        template <> struct is_numeric <unsigned char> { enum { value = true }; };
        template <> struct is_numeric <int> { enum { value = true }; };
        template <> struct is_numeric <unsigned int> { enum { value = true }; };
        template <> struct is_numeric <long int> { enum { value = true }; };
        template <> struct is_numeric <unsigned long int> { enum { value = true }; };
        template <> struct is_numeric <short int> { enum { value = true }; };
        template <> struct is_numeric <unsigned short int> { enum { value = true }; };
        template <> struct is_numeric <long long> { enum { value = true }; };
        template <> struct is_numeric <unsigned long long> { enum { value = true }; };
        template <> struct is_numeric <float> { enum { value = true }; };
        template <> struct is_numeric <double> { enum { value = true }; };
        template <> struct is_numeric <long double> { enum { value = true }; };

        template <bool, class T = void>
        struct enable_if_c {
          typedef T type;
        };

        template <class T>
        struct enable_if_c<false, T> {};

        template <class Cond, class T = void>
        struct enable_if : public enable_if_c<Cond::value, T> {};

        template <bool, class T = void>
        struct disable_if_c {
          typedef T type;
        };

        template <class T>
        struct disable_if_c<true, T> {};

        template <class Cond, class T = void>
        struct disable_if : public disable_if_c<Cond::value, T> {};
}

nodeutil.h包含：

namespace YAML
{
        template <typename T, typename U>
        struct is_same_type {
                enum { value = false };
        };

        template <typename T>
        struct is_same_type<T, T> {
                enum { value = true };
        };

        template <typename T, bool check>
        struct is_index_type_with_check {
                enum { value = false };
        };

        template <> struct is_index_type_with_check<std::size_t, false> { enum { value = true }; };

#define MAKE_INDEX_TYPE(Type) \
        template <> struct is_index_type_with_check<Type, is_same_type<Type, std::size_t>::value> { enum { value = true }; }

        MAKE_INDEX_TYPE(int);
        MAKE_INDEX_TYPE(unsigned);
        MAKE_INDEX_TYPE(short);
        MAKE_INDEX_TYPE(unsigned short);
        MAKE_INDEX_TYPE(long);
        MAKE_INDEX_TYPE(unsigned long);

#undef MAKE_INDEX_TYPE

        template <typename T>
        struct is_index_type: public is_index_type_with_check<T, false> {};

        // messing around with template stuff to get the right overload for operator [] for a sequence
        template <typename T, bool b>
        struct _FindFromNodeAtIndex {
                const Node *pRet;
                _FindFromNodeAtIndex(const Node&, const T&): pRet(0) {}
        };

        template <typename T>
        struct _FindFromNodeAtIndex<T, true> {
                const Node *pRet;
                _FindFromNodeAtIndex(const Node& node, const T& key): pRet(node.FindAtIndex(static_cast<std::size_t>(key))) {}
        };

        template <typename T>
        inline const Node *FindFromNodeAtIndex(const Node& node, const T& key) {
                return _FindFromNodeAtIndex<T, is_index_type<T>::value>(node, key).pRet;
        }
}

Answer 1

你好像在里面包括地狱。你发布的traits.h文件中没有“(”)，但是gcc抱怨“(”)之前的内容。这可能意味着您所包含的宏的名称与此文件中的内容相同。尝试重新排序项目中的包含，看看它是否有任何不同。

Answer 2

我建议您尝试删除“使用命名空间X;”--特别是在X == YAML中。这样，您的错误信息可能会变得更有洞察力--因为看起来您的名称冲突很大。另一个窍门是查看预处理器所吐出的内容--使用G++，您可以使用-E (而不是-c)运行编译行，并将输出输送到文件中。然后，您可以看到编译器得到了什么(而不是原始源，或者预处理程序得到了什么)。