stdin issue

QNX DEVELOPERS Porting
1

Hi,
i have a program which is like this,

FILE *fp;
FILE *temp

fp = fopen (“d.txt”,“r”);

temp = stdin;
stdin = fp;

/some code/

stdin = temp;

In linux it is running fine. But i am getting invalid lvalue in assignment Error. How i can remove this error.
thanks in advance.

2

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main( void )
{
FILE *fp = NULL;
int c;
char *tty = ttyname( STDIN_FILENO );

fp = freopen( "d.txt", "r", stdin );
if ( fp == NULL )
{
	perror ("freopen 1");
}

fprintf (stderr, "stdin modified\n");

while( ( c = fgetchar() ) != EOF ) 
{
        fputchar( c );
}

fp = freopen( tty, "r", stdin );
if ( fp == NULL )
{
	perror ("freopen 2");
}


fprintf (stderr, "stdin restored\n");
while( ( c = fgetchar() ) != EOF ) 
{
        fputchar( c );
}

return (1);
}

3

Thanks ysinitsky. It works for me. But i want to know why the previous was not running?

Thanks once again.

4

Hello Debjyoti,
Consider this fragment from stdio.h
#define stdin (&_CSTD _Stdin) /* standard input file /
#define stdout (&_CSTD _Stdout) / standard output file /
#define stderr (&_CSTD _Stderr) / standard error file */
Thanks,
Yuriy