macro

[nick4ng]

I need to do something like this

#define P1(x) int x##__LINE__ = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

I mean that the macro should be expanded in this way:

int main(int argc, char* argv[])
{
int a3 = 3;
int a4 = 4;
}
but the code above does not work.

How would you implement it?

Thanks

[Victor Bazarov]

ni*****@googlemail.com wrote:

I need to do something like this

#define P1(x) int x##__LINE__ = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

I mean that the macro should be expanded in this way:

int main(int argc, char* argv[])
{
int a3 = 3;
int a4 = 4;
}
but the code above does not work.

How would you implement it?

You need a second level of indirection to use the ## :

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[nick4ng]

On Oct 27, 5:53 pm, "Victor Bazarov" <[e-mail]:

[e-mail] wrote:

I need to do something like this

#define P1(x) int x##__LINE__ = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

I mean that the macro should be expanded in this way:

int main(int argc, char* argv[])
{
int a3 = 3;
int a4 = 4;
}

but the code above does not work.

How would you implement it?

You need a second level of indirection to use the ## :

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

I tried something like this (this is why my macro is called P1: there
was a P2). It looks like it does not work.
I am using VS 2005. The error message at compile time is: error C2374:
'a__LINE__': redefinition...

The code I run is:

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

[Victor Bazarov]

ni*****@googlemail.com wrote:

On Oct 27, 5:53 pm, "Victor Bazarov" <[e-mail]:

>[e-mail] wrote:

>>I need to do something like this

>>#define P1(x) int x##__LINE__ = __LINE__;

>>int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

>>I mean that the macro should be expanded in this way:

>>int main(int argc, char* argv[])
{
int a3 = 3;
int a4 = 4;
}

>>but the code above does not work.

>>How would you implement it?

You need a second level of indirection to use the ## :

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

I tried something like this (this is why my macro is called P1: there
was a P2). It looks like it does not work.
I am using VS 2005. The error message at compile time is: error C2374:
'a__LINE__': redefinition...

The code I run is:

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

Right. Sorry. Another level of indirection is needed:

#define TOGETHER(a,b) a ## b
#define TOGETHER2(a,b) TOGETHER(a,b)
#define P1(x) int TOGETHER2(x,__LINE__) = __LINE__
int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[nick4ng]

On Oct 27, 6:28 pm, "Victor Bazarov" <[e-mail]:

[e-mail] wrote:

On Oct 27, 5:53 pm, "Victor Bazarov" <[e-mail]:

[e-mail] wrote:
I need to do something like this

>#define P1(x) int x##__LINE__ = __LINE__;

>int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

>I mean that the macro should be expanded in this way:

>int main(int argc, char* argv[])
{
int a3 = 3;
int a4 = 4;
}

>but the code above does not work.

>How would you implement it?

You need a second level of indirection to use the ## :

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

I tried something like this (this is why my macro is called P1: there
was a P2). It looks like it does not work.
I am using VS 2005. The error message at compile time is: error C2374:
'a__LINE__': redefinition...

The code I run is:

#define TOGETHER(a,b) a##b
#define P1(x) int TOGETHER(x,__LINE__) = __LINE__;

int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

Right. Sorry. Another level of indirection is needed:

#define TOGETHER(a,b) a ## b
#define TOGETHER2(a,b) TOGETHER(a,b)
#define P1(x) int TOGETHER2(x,__LINE__) = __LINE__
int main(int argc, char* argv[])
{
P1(a);
P1(a);
}

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Thanks!