[vox-tech] file and keyboard input stream in C

[Mike Simons]

On Mon, Mar 03, 2003 at 11:25:31PM -0800, Peter Jay Salzman wrote:
> i have code that reads from stdin via getchar().  i'd like to use the
> program by redirecting a text file to its stdin:
> 
>    ./a.out < myfile.txt
[...]
> unfortunately, i can't use the ncurses input functions.  presumably
> because stdin is attached to a file instead of the keyboard.
> 
> how can i reattach stdin back to the keyboard?

  there is only one stdin, fd 0.  when you run a program like:
./a.out < myfile.txt, that fd is attached to a open copy of the file.
I don't think you can get at the "real" stdin.

  the best thing to do is teach your program to read a list of filenames
on the command line, so you would run it like so:
./a.out myfile.txt, that would leave the stdin of the terminal attached 
to fd 0 for the program to use.

    TTFN,
      Mike


a simple loop like this should do:
 (warning, been doing too much perl recently: there may be syntax errors)

===
for (i = 1; i < argc; i++)
{
  FILE *file;
  if (!(file = fopen(argv[i], "r")))
  { /* file open failed */
    fprintf(stderr, "%s:%d %s error: failed to open \"%s\", $s",
            __FILE__, __LINE__, __FUNCTION__, argv[i], strerror(errno));
  }
  else
  { /* do getc(file) instead of getchar, and whatever logic you do now. 

    fclose(file);
  }
}

/* then work with stdin all you want */
===