The code is attached..My intention is that getchar which usually blocks,should come out after 5 seconds(VTIME).But this is not happening..can anyone tell me the mistake that I make..?

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>

int main()
{
int g,fd;
struct termios oldtio;
struct termios newtio;


g= tcgetattr( STDIN_FILENO, &oldtio );
tcgetattr( fd, &oldtio );
memcpy( &newtio, &oldtio, sizeof(oldtio) );
newtio.c_cc[VTIME] = 50;
newtio.c_cc[VMIN] = 0;

tcflush( STDIN_FILENO, TCIFLUSH );
tcsetattr( fd, TCSANOW, &newtio );

g=getchar();

tcsetattr( fd, TCSANOW, &oldtio );
return 0;
}

You try to modify a device with a file descriptor which is not
opened. Where does it say: fd = open( .... ???

1 members found this post helpful.

sorry..I copied from a wrong place..it is this one that I was suppose to copy...its not working...

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>

int main()
{
int g,fd;
struct termios oldtio;
struct termios newtio;


tcgetattr( STDIN_FILENO, &oldtio );

memcpy( &newtio, &oldtio, sizeof(oldtio) );
newtio.c_cc[VTIME] = 50;
newtio.c_cc[VMIN] = 0;

tcflush( STDIN_FILENO, TCIFLUSH );
tcsetattr( STDIN_FILENO, TCSANOW, &newtio );

g=getchar();

tcsetattr( STDIN_FILENO, TCSANOW, &oldtio );
return 0;
}

VMIN and VTIME work only if you're doing non-canonical I/O. For information on how to set that, see the tcsetattr() man page.

Hope this helps.