Compile error about MACRO

[George2]

Hello everyone,


The compile error of the following code is,

foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
'_'
foo.cpp(7) : error C2065: '_' : undeclared identifier
foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'

I do not know why there is errors. I think in MERGE macro, the value
of parameter a is hello and the value of parameter b is world in my
case, and I defined hello_world to "H E L L O", it should be fine...

Any ideas?

#define MERGE(a,b)  a ## _ ## b
#define hello_world "H E L L O"

int foo()
{
	char* p0;
	p0 = MERGE("hello", "world");

	return 0;
}

thanks in advance,
George

 

[Ian Collins]

Hello everyone,


The compile error of the following code is,

foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
'_'
foo.cpp(7) : error C2065: '_' : undeclared identifier
foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'

I do not know why there is errors. I think in MERGE macro, the value
of parameter a is hello and the value of parameter b is world in my
case, and I defined hello_world to "H E L L O", it should be fine...

No, a is "hello" and b is "world" so your macro produces "hello"_"world".

 

[echo.sj]

Hello everyone,

The compile error of the following code is,

foo.cpp(7) : error C2146: syntax error : missing ';' before identifier
'_'
foo.cpp(7) : error C2065: '_' : undeclared identifier
foo.cpp(7) : error C2143: syntax error : missing ';' before 'string'

I do not know why there is errors. I think in MERGE macro, the value
of parameter a is hello and the value of parameter b is world in my
case, and I defined hello_world to "H E L L O", it should be fine...

Any ideas?

#define MERGE(a,b)  a ## _ ## b
#define hello_world "H E L L O"

int foo()
{
char* p0;
p0 = MERGE("hello", "world");[/QUOTE]
               ~~~~~~~~~~~~~~~~~~~~~~~~MERGE(hello,world);[QUOTE]
return 0;}

thanks in advance,
George