From mboxrd@z Thu Jan  1 00:00:00 1970
From: "saravanaraj v" <saravanaraj.v@gmail.com>
Subject: Trouble reading a character device.
Date: Tue, 16 Dec 2008 12:41:38 +0530
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To: linux-c-programming@vger.kernel.org

Hi,
   I am facing few issues in reading from a character device.
   I have created few character devices using 'mknod' and I am writing
continuously to those devices using 'printk'. After some time I start
another process to read from the device. The open/read is done using
normal sys calls for file open/reading. I have pasted the code for
your ref. When I run this program the read happens for some time and
then there is no progress. I am suspecting that  everything written to
the device before this program was started is read. The flags I tried
for opening the file were RD, RDWR with/without NONBLOCK. The output
was same in all the cases. I tried "cu -l /dev/virt_uart8". It was
able to read continuosuly without any problem. Can someone tell where
the problem is ?


int main(){

int fd,counter=0;
fd = open("/dev/virt_uart8",O_RDONLY|O_NONBLOCK);
if(fd<0) printf("\nError in opeining file");
while(1){

                                        int nread = 0;
                                        nread =
read(fd,buffer,MAX_BUFFER_SIZE-1);
                                        if(nread>0) {
                                                buffer[nread]='\0';
                                                printf("%s",buffer);
                                        }

}
}



Thanks,
Saravanaraj