stdin stderr

I created a program which takes input from stdin like:
myprogram <commandlist.txt

I want if I not redirect stdin (with <file) then my program return a error
message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?

How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

Thanks

> > I created a program which takes input from stdin like:

myprogram <commandlist.txt

I want if I not redirect stdin (with <file) then my program return a error message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?

How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

Thanks

Maybe you could check if any command line arguments where passed (i.e argc

1). This is a bit of a weak way to check, but its the only one I can think
of.

no. argc ==1 <file is not a parameter, is a redirection
to stdin

thanks for second question

[Samuele Armondi]

"<- Chameleon ->" <ch******@hotmail.NOSPAM.com> wrote in message
news:be**********@nic.grnet.gr...

I created a program which takes input from stdin like:
myprogram <commandlist.txt

I want if I not redirect stdin (with <file) then my program return a error message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?

How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

Thanks

Maybe you could check if any command line arguments where passed (i.e argc
1). This is a bit of a weak way to check, but its the only one I can think of.

no. argc ==1 <file is not a parameter, is a redirection
to stdin

thanks for second question

Sorry, I misread... sunday night blues!
-Samuele

[Shane Beasley]

"<- Chameleon ->" <ch******@hotmail.NOSPAM.com> wrote in message news:<be**********@nic.grnet.gr>...

I created a program which takes input from stdin like:
myprogram <commandlist.txt

I want if I not redirect stdin (with <file) then my program return a error
message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?
C++ does not provide a means for doing this. Just take the filename as
a command-line argument and open the file inside your program.

(On Linux, there are system functions to determine whether standard
input is coming from a terminal [i.e., a user, not a file]. Other
systems may have similar capabilities. If you *really* want to do this
[but you really shouldn't], ask a newsgroup related to your system.)
How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

C I/O routines are listed here:

<http://dinkumware.com/htm_cpl/stdio.html>

Take particular note of the ones that begin with the letter 'f'. Note
that stderr is a FILE *.

Note: Use puts/fputs for "sending strings" instead of printf/fprintf
whenever possible. See the following:

<http://groups.google.com/groups?selm=3E8DA58F.6020303%40newsguy.com>
<http://www.securityfocus.com/guest/3342>

Other note: In C++, prefer C++ iostreams over C I/O functions unless
you have good reason not to do so. They're safer and more extensible
(albeit a little slower, but you shouldn't be concerned with that at
this point).

Also, get a good C++ book, like Koenig and Moo's "Accelerated C++" --
it's easier to use and more patient than this newsgroup. :)

- Shane

[Sergey Tursanov]

> I want if I not redirect stdin (with <file) then my program return a error

message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?
Try look isatty function. However it's not a C/C++ standard function but it
is at least
in gcc and VC++ (_isatty in latter case).

How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

In C I could use: fprintf(stderr, "evil comes\n");
In C++ it may be: cerr << "somthing happend" << endl;

Look also perror function.

--
Sergey Tursanov _g***@hippo.ru
to send me an email replace '_' from the address above.

> I created a program which takes input from stdin like:

myprogram <commandlist.txt

I want if I not redirect stdin (with <file) then my program return a error
message and terminate
I do not want to waiting for input from keyboard

Is this possible? How?

How can I send strings to stderr? (e.g. to stdout I send strings with
printf())

Thanks

my approach now is to write something in the end of stdin (a ending header)
is this possible with C/C++? How?

[Shane Beasley]

"<- Chameleon ->" <ch******@hotmail.NOSPAM.com> wrote in message news:<be**********@nic.grnet.gr>...

my approach now is to write something in the end of stdin (a ending header)
is this possible with C/C++? How?

How (or why) would you propose to *write* something to *standard
input*, since "input" means "for reading" (contrast with "output")?
stdin is for reading, not for writing.

This means, incidentally, that the answer to your question is "no."

If you meant something else, please rephrase your question.

- Shane