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Christopher Benson-Manica
Guest
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 Posted: Fri Feb 27, 2004 4:11 pm Post subject: Problem with convoluted function pointer |
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Given
typedef bool (TMyType::* FTYPE)(const void*,unsigned int, unsigned
int, unsigned int);
class TMyType{
public:
bool Send( const void *, unsigned int, unsigned int, unsigned int );
};
class TMyDerivedType : public TMyType
{
private:
A a;
public:
TMyDerivedType() : a(&TMyType::Send) {}
};
class A
{
private:
FTYPE f;
public:
void do_stuff() {f(NULL,1,2,3);}
A( FTYPE func ) {f=func;}
};
Why is f(NULL...) "call of nonfunction?" What have I done wrong?
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.
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John Harrison
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| Posted: Fri Feb 27, 2004 4:23 pm Post subject: Re: Problem with convoluted function pointer |
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"Christopher Benson-Manica" <ataru (AT) nospam (DOT) cyberspace.org> wrote
| Quote: | Given
typedef bool (TMyType::* FTYPE)(const void*,unsigned int, unsigned
int, unsigned int);
class TMyType{
public:
bool Send( const void *, unsigned int, unsigned int, unsigned int );
};
class TMyDerivedType : public TMyType
{
private:
A a;
public:
TMyDerivedType() : a(&TMyType::Send) {}
};
class A
{
private:
FTYPE f;
public:
void do_stuff() {f(NULL,1,2,3);}
A( FTYPE func ) {f=func;}
};
Why is f(NULL...) "call of nonfunction?" What have I done wrong?
|
Not followed the correct syntax for pointers to member functions
From memory,
(this->*f)(NULL,1,2,3);
john
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Rob Williscroft
Guest
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| Posted: Fri Feb 27, 2004 4:23 pm Post subject: Re: Problem with convoluted function pointer |
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Christopher Benson-Manica wrote in news:c1nq86$p95$1 (AT) chessie (DOT) cirr.com:
| Quote: | Given
typedef bool (TMyType::* FTYPE)(const void*,unsigned int, unsigned
int, unsigned int);
class TMyType{
public:
bool Send( const void *, unsigned int, unsigned int, unsigned int );
};
class TMyDerivedType : public TMyType
{
private:
A a;
public:
TMyDerivedType() : a(&TMyType::Send) {}
};
class A
{
private:
FTYPE f;
public:
void do_stuff() {f(NULL,1,2,3);}
A( FTYPE func ) {f=func;}
};
Why is f(NULL...) "call of nonfunction?" What have I done wrong?
|
Member pointers only contain a reference to the member not the object,
to call via such a pointer you need an object:
FTYPE f = &TMyType::send;
TMyType obj, *ptr = &obj;
(obj.*f)( NULL, 1, 2, 3 );
(ptr->*f)( NULL, 1, 2, 3 );
HTH.
Rob.
--
http://www.victim-prime.dsl.pipex.com/
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Christopher Benson-Manica
Guest
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| Posted: Fri Feb 27, 2004 4:32 pm Post subject: Re: Problem with convoluted function pointer |
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John Harrison <john_andronicus (AT) hotmail (DOT) com> spoke thus:
| Quote: | typedef bool (TMyType::* FTYPE)(const void*,unsigned int, unsigned
int, unsigned int);
class TMyType{
public:
bool Send( const void *, unsigned int, unsigned int, unsigned int );
};
class TMyDerivedType : public TMyType
{
private:
A a;
public:
TMyDerivedType() : a(&TMyType::Send) {}
};
class A
{
private:
FTYPE f;
public:
void do_stuff() {f(NULL,1,2,3);}
A( FTYPE func ) {f=func;}
};
|
(left for context)
| Quote: | (this->*f)(NULL,1,2,3);
|
Okay, thanks - that works. Unfortunately, now I'm informed that
TMyType is not a public base class of A... Now what? I should
probably note here that TMyDerivedType has it's own Send() function,
with a different signature.
(Thanks so much for continuing to bear with me!)
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.
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Christopher Benson-Manica
Guest
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| Posted: Fri Feb 27, 2004 4:40 pm Post subject: Re: Problem with convoluted function pointer |
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Christopher Benson-Manica <ataru (AT) nospam (DOT) cyberspace.org> spoke thus:
| Quote: | (this->*f)(NULL,1,2,3);
Okay, thanks - that works. Unfortunately, now I'm informed that
TMyType is not a public base class of A... Now what? I should
probably note here that TMyDerivedType has it's own Send() function,
with a different signature.
|
Ah, I see what I wanted - not MyType::Send, but this->MyType::Send,
changing the typedef accordingly of course. At least it compiles
now...
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.
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