pre-processor string replacement

[sam_cit]

Hi Everyone,

I have the following question regarding string replacement
pre-processor statement,

#define status "23"
#define status "44"

int main()
{
printf("%s\n", status);
}

this works fine and prints 44

where as

#define status "23"
#define status1 status

int main()
{
printf("%s\n", status);
}

prints 23, string replacement occurs on the pre-processor statement
itself, which is not in case 1, why is it so?
Can anyone help me on this?

[Alan Curry]

In article <11************ *********@q2g20 00cwa.googlegro ups.com>,
<sa*****@yahoo. co.inwrote:

>Hi Everyone,

I have the following question regarding string replacement
pre-processor statement,

#define status "23"
#define status "44"

This part has been explained already, but the second part, where your
question actually becoms interesting, hasn't:

#define status "23"
#define status1 status

int main()
{
printf("%s\n", status1);

[your correction from another post has been applied to the previous line]

}

prints 23, string replacement occurs on the pre-processor statement
itself, which is not in case 1, why is it so?

It is not so. What really happens macro replacement happens repeatedly.

The definitions that the preprocessor is remembering are conceptually
status ="23"
status1 =status
just like they look in the #defines.

The preprocessor sees the "status1" which is recognizes as a macro, and
replaces it with "status". Then it sees the "status" that is recognizes as a
macro, and replaces it with the quoted 23.

--
Alan Curry
pa****@world.st d.com

[Thad Smith]

sa*****@yahoo.c o.in wrote:

>

>>#define status "23"
#define status "44"

What did you expect to see?

i expect first statement to replace status of second statement with
23, so it would be

#define "23" "43"...

There are a few places that macro substitution of preprocessing tokens
doesn't occur. The following are some (there may be others):

1. identifier following #define and #undef
2. argument names in a function-like macro definition
3. identifier following #ifdef and #ifndef
4. identifier following defined operator in #if, #elif statement
5. identifiers following #error
6. identifiers following #pragma STDC or equivalent _Pragma ("STDC ...")
operator (C99 only)
7. inside string literals
8. inside character constants
9. inside h-character-sequence and q-character-sequence (within <and
"") on #include line
10. identifiers in skipped text after a false #if
(#elif/#ifdef/#ifndef), including text on the same line after #<pp operator>
11. comments (they don't exist in translation phase 4)

Does anyone know of any other places within the program text that macros
are not expanded?

--
Thad