Function Pointers that Won't compile

[JMK]

Help my class won't complile...


typedef void (* TestFunc)();
typedef std::map<int, TestFunc > FunctionMap ;


class CMyClass
{
public:

FunctionMap m_Map ;

COracleObjectFactory()
{
m_FuncMap[1] = TestFunction; // Errors
m_FuncMap[2] = TestFunction2; // Errors
}

void TestFunction()
{
// Some Instructions
}

void TestFunction2()
{
// Some Instructions
}

} ;






I'm getting the following error

error C2440: '=' : cannot convert from 'void (__thiscall CMyClass::*)(void)' to 'void (__cdecl *)(void)'
There is no context in which this conversion is possible.

All help grateful accepted... :)

thanks in advance

Martin

[James Curran]

You've defined TestFunc as a pointer to a global (non-member) function, and then tried to stick member functions in it. Either change TestFunction?() to static member functions, or change the typedef to:typedef void (* CMyClass::TestFunc)();



Truth,
James
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[Igor Soukhov]

In your code:


typedef void (* TestFunc)();




you "create" a type of pointer to a function what takes NO params... Each NON-STATIC member function (like TestFunction or TestFunction2) have an implicit this parameter (used to access instance member data) - so In your case you can either use static member functions (but you wont be able to access member data from static function):


#include <map>

typedef void (CMyClass::* TestFunc)();
typedef std::map<int, TestFunc > FunctionMap ;


class CMyClass
{
public:

FunctionMap m_Map;

void COracleObjectFactory()
{
m_Map[1] = TestFunction; // Errors
m_Map[2] = TestFunction2; // Errors
}

void TestFunction()
{
// Some Instructions
}

void TestFunction2()
{
// Some Instructions
}

} ;




or use a pointers to a member functions:


#include <map>

typedef void (* TestFunc)();
typedef std::map<int, TestFunc > FunctionMap ;


class CMyClass
{
public:

FunctionMap m_Map;

void COracleObjectFactory()
{
m_Map[1] = TestFunction; // Errors
m_Map[2] = TestFunction2; // Errors
}

static void TestFunction()
{
// Some Instructions
}

static void TestFunction2()
{
// Some Instructions
}

} ;







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Best regards,

-----------
Igor Soukhov (Brainbench/Tekmetrics ID:50759)
igor@soukhov.com | ICQ:57404554 | http://soukhov.com

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