Impossible pointer to function assignment?

[FransJ]

(How) can I let a "pointer to a function" variable point to a function that is specified by another variable?

Example:
char rec_value[20];
int (*rcv_mail[2])(char *msg);
extern int ser_rcv_mail(char *msg);
strcpy (rec_value,"ser_rcv_mail"

Is it possible to let rcv_mail[0] point to the function ser_rcv_mail() by using the contents of the rec_value variable, something equal to "rcv_mail[0] = ser_rcv_mail;"?

 

[ankan]

I think...
rcv_mail[0] = ser_rcv_mail;
...should work fine. But you can't use the contents of the rec_value variable since its just a character array, and the compiler isn't going to look at it in any other sense.

By the way, "(How) can I let a "pointer to a function" variable point to a function that is specified by another variable?", you can't specify a function by some variable except by pointers. I think.
Ankan.

Please do correct me if I am wrong. s-)

 

[Jay1Roy]

Ankan,

You think a lot!! : But u r right ;-)

FransJ, what u r tryin isnt really possible as it would be mere a string of characters not a function name...

Chow!

Roy

 

[FransJ]

Ok Ankan and Roy,

I was afraid you were going to write this :-(, but (of course) thanks for your help.


Frans

 

[Guest_imported]

Hehe..... one question, how to do pointer to a function into a c++ class?

i tried:

class lala
{
int f1(int, int);
int f2(int, int);
int (lala::*pf)(int, int);
};

int lala::f1(int a, int b)
{
return a+b;
}

int lala::f2(int a, int b)
{
return a-b;
}

void main()
{
lala l;
int a = 5, b = 6, c, d;

l.pf = l.f1;

c = l.pf(a, b); //ERR: term does not evaluate to a function

l.pf = l.f2;

d = l.pf(a, b); //ERR: term does not evaluate to a function

printf("Res: %d %d\n", c, d);
}


please send me answer to lorien@postmaster.co.uk

TXS!!!!

 

[Guest_imported]

hi lorien

run this code

#include<iostream.h>

class lala
{
public:

lala()
{
pf[0]=lala::f1;
pf[1]=lala::f2;
};
int choice(int,int,int);
int f1(int, int);
int f2(int, int);
int (lala::*pf[2])(int, int);
};

int lala::f1(int a, int b)
{
return a+b;
}

int lala::f2(int a, int b)
{
return a-b;
}



int lala::choice(int count,int a=0,int b=0)
{

return (this->*pf[count])(a,b);
}



void main()
{
lala l;
int a = 5, b = 6, c, d;

c=l.choice(0,a,b);
d=l.choice(1,a,b);
printf(&quot;Res: %d %d\n&quot;, c, d);
}
hope this helps

bye
yogesh