l i n u x - u s e r s - g r o u p - o f - d a v i s
Next Meeting:
July 7: Social gathering
Next Installfest:
Latest News:
Jun. 14: June LUGOD meeting cancelled
Page last updated:
2003 Mar 04 08:30

The following is an archive of a post made to our 'vox-tech mailing list' by one of its subscribers.

Report this post as spam:

(Enter your email address)
Re: [vox-tech] file and keyboard input stream in C
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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

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.


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));
  { /* do getc(file) instead of getchar, and whatever logic you do now. 


/* then work with stdin all you want */
vox-tech mailing list

LUGOD Group on LinkedIn
Sign up for LUGOD event announcements
Your email address:
LUGOD Group on Facebook
'Like' LUGOD on Facebook:

Hosting provided by:
Sunset Systems
Sunset Systems offers preconfigured Linux systems, remote system administration and custom software development.

LUGOD: Linux Users' Group of Davis
PO Box 2082, Davis, CA 95617
Contact Us

LUGOD is a 501(c)7 non-profit organization
based in Davis, California
and serving the Sacramento area.
"Linux" is a trademark of Linus Torvalds.

Sponsored in part by:
EDGE Tech Corp.
For donating some give-aways for our meetings.