Re: unhappy with current.h

[Richard B. Johnson]

On Mon, 14 Oct 2002, Daniele Lugli wrote:

> I recently wrote a kernel module which gave me some mysterious problems.
> After too many days spent in blood, sweat and tears, I found the cause:
> 
> *** one of my data structures has a field named 'current'. ***
> 
> Pretty common word, isn't it? Would you think it can cause such a
> trouble? But in some of my files I happen to indirectly include
> <asm/current.h> (kernel 2.4.18 for i386), containing the following line:
> 
> #define current get_current()
> 
> so that my structure becomes the owner of a function it has never asked
> for, while it looses a data member. gcc has nothing to complain about
> that.
>

This cannot be the reason for your problem. The name of a structure
member has no connection whatsoever with the name of any function or
definition.

The following code will correctly write "Hello world!" to the screen
even though the text initializes a member of a structure called "current"
while "current" has been defined to be a function called puts.

#include <stdio.h>
#define current puts
struct foo {
    char *current;
    int foo;
    } bar; 
main()
{
    bar.current = "Hello world!";
    current(bar.current);
    return 0;
}

For your code to get "confused", you really have something else
wrong. That said, some name-space polution may make it difficult
to find the problem. For instance, a structure member is expected
to have a ";" after it. It's possible for some previous definition
to make a syntax error invisible.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
The US military has given us many words, FUBAR, SNAFU, now ENRON.
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