your problems is a C syntax problem
when you use the comma it takes "<1>" as the format
string and the "[helloinit1]\n" as an argument.
In C when you have two string constants together it
concatenates them ie printk("<1>" "[helloinit1]\n");
becomes printk("<1>[helloinit1]\n");
--- Smith Norton <smith.norton@xxxxxxxxx> wrote:
> I am sorry, I couldn't find answers to the two
> questions I have asked
> in the link you have given.
>
> Can someone kindly answer the two questions I have
> asked? I am a
> newbie in this field, hence I need a little help to
> get started with
> this.
>
> - Smith.
>
> On 12/12/06, Christophe Lucas <clucas@xxxxxxxxxxxxx>
> wrote:
> > Smith Norton (smith.norton@xxxxxxxxx) wrote:
> > > I am trying the following kernel module in
> Ubuntu-6.06 LTS. I am using
> > > the kernel that came along with Ubuntu.
> > >
> > > #include <linux/module.h>
> > > #include <linux/kernel.h>
> > > #include <linux/init.h>
> > >
> > > MODULE_LICENSE("GPL");
> > >
> > > static int __init helloinit(void)
> > > {
> > > printk(KERN_ALERT, "[helloinit1]\n");
> >
> > printk(KERN_ALERT "[helloinit1]\n");
> > => without coma.
> >
> >
> > > printk("[helloinit2]\n");
> > > return 0;
> > > }
> > >
> > > static void __exit helloexit(void)
> > > {
> > > printk(KERN_ALERT, "[helloexit1]\n");
> > > printk("[helloexit2]\n");
> > > }
> > >
> > > module_init(helloinit);
> > > module_exit(helloexit);
> > >
> > > After compiling it with 'make', I 'insmod' it
> and then 'rmmod' it
> > > twice. The last few lines of /var/log/kern.log
> are as follows:-
> > >
> > > Dec 11 23:14:40 localhost kernel:
> [4295711.583000] <1><1>[helloinit2]
> > > Dec 11 23:14:45 localhost kernel:
> [4298099.296000] [helloexit2]
> > > Dec 11 23:15:22 localhost kernel:
> [4298136.092000] [helloinit2]
> > > Dec 11 23:15:27 localhost kernel:
> [4298141.000000] [helloexit2]
> > >
> > > 1. According to LKMPG '[helloinit1]' and
> '[helloexit1]' should have
> > > been printed. Why weren't they printed. Instead
> the <1> (KERN_ALERT)
> > > was printed. Here are all the macro defintions
> in my Ubuntu box:-
> > >
> > > smith@smithbox:~/kernel/exp$ grep "define"
> > > /usr/src/linux-headers-`uname
> -r`/include/linux/kernel.h | grep
> > > "KERN_"
> > > #define KERN_EMERG "<0>" /* system is
> unusable */
> > > #define KERN_ALERT "<1>" /* action must
> be taken immediately */
> > > #define KERN_CRIT "<2>" /* critical
> conditions */
> > > #define KERN_ERR "<3>" /* error
> conditions */
> > > #define KERN_WARNING "<4>" /* warning
> conditions */
> > > #define KERN_NOTICE "<5>" /* normal but
> significant condition */
> > > #define KERN_INFO "<6>" /* informational
> */
> > > #define KERN_DEBUG "<7>" /* debug-level
> messages */
> > >
> > > smith@smithbox:~/kernel/exp$ grep "int printk("
> > > /usr/src/linux-headers-`uname
> -r`/include/linux/kernel.h
> > > asmlinkage int printk(const char * fmt, ...)
> > > static inline int printk(const char *s, ...)
> > > static inline int printk(const char *s, ...) {
> return 0; }
> > >
> > > Why aren't '[helloinit1]' and '[helloexit1]'
> getting printed?
> > >
> > > 2. According to the sequence of statements, the
> output should have been:-
> > >
> > > <1>[helloinit2]
> > > <1>[helloexit2]
> > > <1>[helloinit2]
> > > <1>[helloexit2]
> > >
> > > But the output instead is:-
> > >
> > > <1><1>[helloinit2]
> > > [helloexit2]
> > > [helloinit2]
> > > [helloexit2]
> > >
> > > Why?
> >
> > See :
> http://www.xml.com/ldd/chapter/book/ch04.html#t1
> >
> > Have a nice day,
> >
> > Regards,
> >
> > Christophe
> >
>
> --
> Kernelnewbies: Help each other learn about the Linux
> kernel.
> Archive:
> http://mail.nl.linux.org/kernelnewbies/
> FAQ: http://kernelnewbies.org/faq/
>
>
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