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>Common Routines</H1
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><TT
CLASS="FUNCTION"
>printk()</TT
>
<TT
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>include/linux/kernel.h</TT
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> <TT
CLASS="FUNCTION"
>printk()</TT
> feeds kernel messages to the
console, dmesg, and the syslog daemon. It is useful for debugging
and reporting errors, and can be used inside interrupt context,
but use with caution: a machine which has its console flooded with
printk messages is unusable. It uses a format string mostly
compatible with ANSI C printf, and C string concatenation to give
it a first "priority" argument:
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>printk(KERN_INFO "i = %u\n", i);
</PRE
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> See <TT
CLASS="FILENAME"
>include/linux/kernel.h</TT
>;
for other KERN_ values; these are interpreted by syslog as the
level. Special case: for printing an IP address use
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>__u32 ipaddress;
printk(KERN_INFO "my ip: %d.%d.%d.%d\n", NIPQUAD(ipaddress));
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> <TT
CLASS="FUNCTION"
>printk()</TT
> internally uses a 1K buffer and does
not catch overruns. Make sure that will be enough.
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> You will know when you are a real kernel hacker
when you start typoing printf as printk in your user programs :)
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> Another sidenote: the original Unix Version 6 sources had a
comment on top of its printf function: "Printf should not be
used for chit-chat". You should follow that advice.
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><TT
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>copy_[to/from]_user()</TT
>
/
<TT
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>get_user()</TT
>
/
<TT
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>put_user()</TT
>
<TT
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>include/asm/uaccess.h</TT
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