Eliminate all of the console output message

Don Hiatt Don_Hiatt at pmc-sierra.com
Tue Sep 26 16:03:58 UTC 2006


Append this to your kernel command line "... console=/dev/null" and
all messages will go to the bit bucket.

Cheers,

don
 

-----Original Message-----
From: uclibc-bounces at uclibc.org [mailto:uclibc-bounces at uclibc.org] On Behalf Of Sterling Augustine
Sent: Tuesday, September 26, 2006 8:48 AM
To: Jan-Benedict Glaw
Cc: uclibc at uclibc.org; colin
Subject: Re: Eliminate all of the console output message

Why not just redirect stdout and stderr to /dev/null? Google for how to do this programmatically, internal to your application. It's not hard.

The problem you have is that an application could be calling "write" 
directly, without using any libc calls at all.



Jan-Benedict Glaw wrote:
> On Tue, 2006-09-26 17:40:42 +0800, colin <colin at realtek.com.tw> wrote:
> 
>>I am trying to eliminate all of the console output message of the 
>>embedded application.
>>What I do is like this:
>>    #define puts do { } while (0)
>>
>>printf and putchar will also be replaced by this way.
>>Is it safe to do this?
> 
> 
> Consider:
> 
> 	while (1) {
> 		printf ("Next element: %d\n", n++);
> 		if (n == 10)
> 			break;
> 	}
> 
> So generally, this is not save, because you still need to evaluate the 
> arguments.
> 
> However, in the Linux kernel uses something similar for embedded 
> systems (linux-2.6.x/include/linux/kernel.h):
> 
> 150	static inline int printk(const char *s, ...)
> 151		__attribute__ ((format (printf, 1, 2)));
> 152	static inline int printk(const char *s, ...) { return 0; }
> 
> You can use something similar to still perform argument evaluation 
> while optimizing out the whole call.  However, if you even miss to 
> include your header containing this define, the program will still 
> pull the function at link time.  Also keep in mind that some libraries 
> will have wrapper macros for these funcions, pointing to actual 
> differently named functions...
> 
> MfG, JBG
> 
> 
> 
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