[En-Nut-Discussion] freopen(..)

[Bernard Fouché]

Harald Kipp wrote:

> Hi Bernard,
>
> At 11:52 27.10.2005 +0200, you wrote:
>
>> stdout=freopen("uart0","w",stdout);
>
>
> This is used wrongly. The return value should not be
> assigned to stdout, but only checked for failure.
>
freopen() is supposed to give back a FILE *, not just a test value.

Using stdout=freopen(somefile,someflags,stdout); is rather usual since 
it allows one to reuse code referencing stdout to send data somewhere 
instead of the 'normal' stdout. There is always trouble when a known 
function like that has a behavior different from the standard one.

Now I try to read data from uart0. I've tried to use stdout for both ways:

freopen("uart0","r+",stdout); -> I can write but fgetc(stdout) crashes 
the application.

I've tried:

freopen("uart0","w",stdout);
freopen("uart0","r",stdin);
fgetc(stdin);

It also crash.

What is the correct way to be able to use streams for bidirectionnal 
i/o's with a uart0 ?

Thanks

  Bernard