[ECOS] read and write to standerd IO

[Jonathan Larmour]

Satoshi Sasaki wrote:
> 
> read() failed if the following programs are executed.
> test_prog() is executed as a thread.
> 
> int test_prog()
> {
>  char tmpbuf[5];
> 
>  write(1,"XXXX",4);
>  read(0,&tmpbuf,4);
[snip]
> 
> Can I use standard input(fd number 0)?

Yes. The issue is that in the default configuration, stdio uses 
/dev/ttydiag, which is a TTY device over a "pretend" serial device that 
actually uses the HAL diagnostic I/O routines. These routines may or may 
not support input, and more importantly won't work if you're communicating 
via GDB.

> Or is it necessary to call open() again from a user program?

You can do that, or you can change CYGDAT_LIBC_STDIO_DEFAULT_CONSOLE to 
select the TTY device you really want.

Jifl
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