macros

[Bill Cunningham]

I was browsing the linux kernel source and came across something I've never
seen. Here's an example

#define (thismacro)
#define (1<<(thismacro))

What is this doing? Why the parenthesis around the macro defines, on each
line?

Bill

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[Joona I Palaste]

Bill Cunningham <no****@net.net> scribbled the following:

I was browsing the linux kernel source and came across something I've never
seen. Here's an example #define (thismacro)
#define (1<<(thismacro)) What is this doing? Why the parenthesis around the macro defines, on each
line?

I don't think #define (1<<(thismacro)) is valid C syntax at all.

--
/-- Joona Palaste (pa*****@cc.helsinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"I am looking for myself. Have you seen me somewhere?"
- Anon

[Nils Petter Vaskinn]

On Thu, 16 Oct 2003 02:32:43 -0400, Bill Cunningham wrote:

I was browsing the linux kernel source and came across something I've never
seen. Here's an example

#define (thismacro)
#define (1<<(thismacro))

What is this doing? Why the parenthesis around the macro defines, on each
line?

Doesn't look like C, are you sure you didn't miss anything in your
example? It might be a gcc specific thing though, but a quick glance at
the gcc info pages didn't shed any light on it.

Looking at the actual usage instead of your example might help shed some
light on it.
Kernel version?
File?
Line?

regards
--
NPV

"the large print giveth, and the small print taketh away"
Tom Waits - Step right up

[Christopher Benson-Manica]

Joona I Palaste <pa*****@cc.helsinki.fi> spoke thus:

#define (thismacro)
#define (1<<(thismacro))

I don't think #define (1<<(thismacro)) is valid C syntax at all.

Neither is #define (thismacro), for that matter, right? gcc says that macro
names must be identifiers...
--
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.

[Bill Cunningham]

"Nils Petter Vaskinn" <[e-mail]> wrote in message
news:pa****************************@spam.for.me.in valid...

On Thu, 16 Oct 2003 02:32:43 -0400, Bill Cunningham wrote:

I was browsing the linux kernel source and came across something I've never seen. Here's an example

#define (thismacro)
#define (1<<(thismacro))

What is this doing? Why the parenthesis around the macro defines, on each line?

Doesn't look like C, are you sure you didn't miss anything in your
example? It might be a gcc specific thing though, but a quick glance at
the gcc info pages didn't shed any light on it.

Looking at the actual usage instead of your example might help shed some
light on it.
Kernel version?
File?
Line?

regards

It figures. Now I can't find it but I believe it had something to do with
sys calls or calling sys calls. I'll keep looking. I'm almost sure I've seen
code like

#define (something)

before in a header or source file. But if it's a syntax error, maybe I'm
mistaken.

Bill

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