Re: Redirect stderr to ncurses window

[Thomas Dickey]

On Mon, 23 May 2011, Jeff Barnes wrote:

> I've seen posts and blogs advising against this, but I need to grab 
> debug output from a library and print it to an ncurses window. I've 
> tried code like the following, but it doesn't work and corrupts the 
> terminal window. What do I have to do to grab the library stderr output 
> and wprintw it to a WINDOW?
>
> I'm locking down all ncurses function calls with the same mutex.
>
> Am I "barking up the wrong tree?"
>
> Thanks for any help.
>
> void
> stderr_thread_func(void *data) {
>  int outp[2], old, len;
>  char buf[1024] = {0};
>  old = dup(stderr);
>  if (pipe(outp) != 0) {
>    g_mutex_lock(curses_mutex);
>    wprintw(console.msgw, "Pipe failed\n");
>    wrefresh(console.msgw);
>    g_mutex_unlock(curses_mutex);
>    return;
>  }
>  dup2(outp[1], stderr);
>  close(outp[1]);

dup/dup2 take an integer parameter, e.g., something (in this context) like 
fileno(stderr).  compiler warnings are useful for finding these problems.

I added code to dialog recently (the dlg_popen function in prgbox.c)
which does something like this.

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net