binary '<' : no operator found which takes a left-hand operand of type

Question

I am getting the following error messages when i compile this code in visual studio 2005

struct SymEntry

{

inline SymEntry(ProgramCounter addr, const std::string& symbol)

: m_addr(addr), m_symbol(symbol)

{}

friend bool operator<(const SymEntry&, ProgramCounter);

friend bool operator<(const SymEntry&, const SymEntry&);

ProgramCounter m_addr;

std::string m_symbol;

};

typedef std::vector<SymEntry> SymbolList;

typedef std::vector<SymEntry*> SymbolPtrList;

inline bool operator<(const SymEntry& left, ProgramCounter addr)

{

return left.m_addr < addr;

}

inline bool operator<(const SymEntry& left, const SymEntry& right)

{

return left.m_addr < right.m_addr;

}

c:\program files\microsoft visual studio 8\vc\include\xutility(267) : error C2678: binary '<' : no operator found which takes a left-hand operand of type 'const ProgramCounter' (or there is no acceptable conversion)

c:\look\dev\make\toolslib\symbolmap_int.h(15): could be 'bool operator <(const SymEntry &,ProgramCounter)' [found using argument-dependent lookup]

c:\look\dev\make\toolslib\symbolmap_int.h(16): or 'bool operator <(const SymEntry &,const SymEntry &)' [found using argument-dependent lookup]

while trying to match the argument list '(const ProgramCounter, SymEntry)'

c:\program files\microsoft visual studio 8\vc\include\algorithm(2268) : see reference to function template instantiation 'bool std::_Debug_lt<SymEntry,_Ty>(_Ty1 &,const _Ty2 &,const wchar_t *,unsigned int)' being compiled

with

[

_Ty=ProgramCounter,

_Ty1=SymEntry,

_Ty2=ProgramCounter

]

===============================================================================================

c:\program files\microsoft visual studio 8\vc\include\algorithm(2280) : see reference to function template instantiation '_FwdIt std::_Lower_bound<std::_Vector_iterator<_Ty,_Alloc>,unsigned int,__w64 int>(_FwdIt,_FwdIt,const unsigned int &,_Diff *)' being compiled

with

[

_FwdIt=std::_Vector_iterator<SymEntry,std::allocator<SymEntry>>,

_Ty=SymEntry,

_Alloc=std::allocator<SymEntry>,

_Diff=__w64 int

]

c:\dev\make\toolslib\symbolmap.cpp(77) : see reference to function template instantiation '_FwdIt std::lower_bound<std::_Vector_iterator<_Ty,_Alloc>,ProgramCounter>(_FwdIt,_FwdIt,const unsigned int &)' being compiled

with

[

_FwdIt=std::_Vector_iterator<SymEntry,std::allocator<SymEntry>>,

_Ty=SymEntry,

_Alloc=std::allocator<SymEntry>

]

 

Answer 1

Any help in this regard would he helpful.

Answer 2

You didn't make an operator < that takes a ProgramCounter as a left-hand operand. You need an operator of the form

bool operator<( ProgramCounter addr, const SymEntry& right )

Answer 3

It Reports the same error. This Code works in Vc++6.0 and doesnt in Visual Studio 5.0

c:\program files\microsoft visual studio 8\vc\include\xutility(265) : error C2678: binary '<' : no operator found which takes a left-hand operand of type 'SymEntry' (or there is no acceptable conversion)
        c:\symbolmap_int.h(15): could be 'bool operator <(ProgramCounter,const SymEntry &)' [found using argument-dependent lookup]
        c:\symbolmap_int.h(16): or 'bool operator <(const SymEntry &,const SymEntry &)' [found using argument-dependent lookup]
        while trying to match the argument list '(SymEntry, const ProgramCounter)'
        c:\program files\microsoft visual studio 8\vc\include\algorithm(2268) : see reference to function template instantiation 'bool std::_Debug_lt<SymEntry,_Ty>(_Ty1 &,const _Ty2 &,const wchar_t *,unsigned int)' being compiled
        with
        [
            _Ty=ProgramCounter,
            _Ty1=SymEntry,
            _Ty2=ProgramCounter
        ]
        c:\program files\microsoft visual studio 8\vc\include\algorithm(2280) : see reference to function template instantiation '_FwdIt std::_Lower_bound<std::_Vector_iterator<_Ty,_Alloc>,unsigned int,__w64 int>(_FwdIt,_FwdIt,const unsigned int &,_Diff *)' being compiled
        with
        [
            _FwdIt=std::_Vector_iterator<SymEntry,std::allocator<SymEntry>>,
            _Ty=SymEntry,
            _Alloc=std::allocator<SymEntry>,
            _Diff=__w64 int
        ]
        c:\pam.look\dev\make\toolslib\symbolmap.cpp(77) : see reference to function template instantiation '_FwdIt std::lower_bound<std::_Vector_iterator<_Ty,_Alloc>,ProgramCounter>(_FwdIt,_FwdIt,const unsigned int &)' being compiled
        with
        [
            _FwdIt=std::_Vector_iterator<SymEntry,std::allocator<SymEntry>>,
            _Ty=SymEntry,
            _Alloc=std::allocator<SymEntry>
        ]

Answer 4

It looks like you need both variants:

bool operator<(ProgramCounter, const SymEntry&)
bool operator<(const SymEntry&, ProgramCounter)

Answer 5

Thanks Jonathan...It worked...