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From: "Dinesh  Gandhewar" <dinesh_gandhewar@rediffmail.com>
To: mlist-linux-kernel@nntp-server.caltech.edu
Subject: volatile variable
Date: 1 Aug 2003 10:57:06 -0000	[thread overview]
Message-ID: <20030801105706.30523.qmail@webmail28.rediffmail.com> (raw)

Hello,

If a system call is having following code.

add current process into wait quque ;
while (1)
{  set task state INTERRUPTIBLE ;
    if (a > 0)
      break ;
    schedule() ;
}
set task state RUNNING ;
remove current from wait queue ;


If an interrupt service is having following code

set a = 512 ;

'a' is a global variable shared in ISR and system call

Do I need to define a as 'volatile int a ;' ? Why?

Thanks & Regards,
Dinesh




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             reply	other threads:[~2003-08-01 10:58 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-01 10:57 Dinesh  Gandhewar [this message]
2003-08-01 11:38 ` volatile variable Richard B. Johnson
2003-08-11 13:33   ` David Woodhouse
2003-08-11 14:06     ` Richard B. Johnson
2003-08-11 14:37       ` Jakub Jelinek
2003-08-11 14:38       ` David Woodhouse
2003-08-11 14:40       ` David Howells
2003-08-11 14:49       ` Mike Galbraith
2003-08-11 17:07       ` Robert Love
2003-08-02 14:52 Harm Verhagen

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