ahhhh...I had a problem the other day the I think may have something to do
with this.  The following piece of code will clarify:

#include <stdio.h>
main()
{
 FILE *otherptr ;

 fprintf(stdprn,"This goes to the system printer!!") ;
 otherptr = strprn ;
 fprintf(otherptr,"And so does this...(on the same line even)\n") ;
 fclose(otherptr) ;
 fprintf(stdprn,"But this doesn't....???????\n") ;

BTW, this was using IBM C 1.0 (can anybody tell me roughly what MSC version
this is??).  fclose seems to have a FILE * linked in some manner with the
corresponding system file handle.  When you have two pointers sharing a handle
(as seems to happen in this case), fclose seems to close out both the system
handle as well as the FILE *.
Not the question is: Does this make sense?   I have been able to convince my
self both ways.  Anybody got a good argument!!

Michael Hunter         UUCP  : ....{seismo, rutgers, ames}!cit-vax!oxy!bagpiper

Your problem is very simple.

The type of stdprn is a pointer to FILE.  You coppied the pointer
value from stdprn into otherptr.  When you closed otherprinter you
were pointing to te same thing as stdprn.  Since both of the
pointers are identical [and therefore have the same MS-DOS file handle]
the single handle was closed.  Remember type FILE is a structure
one entry of which is the file handle is only one part.  This also
holds true for any UNIX STREAM.

Instead of the asignment you did in the code fragment, you should have
either used dup() or dup2() functions so that you had 2 seprate files
open to the same device.  NOTE: on MS-DOS versions before 3.0 the close
will still cause futrue writes to fail [do to an ms-dos bug] because
the close routine will still sometimes close both file handles (this
from my Microsoft C manual.)  The code works correctly for 3.0 ms-dos
and above.

Robert ("So who asked you anyway?") White.

It suprises you that stdprn is closed after you close it?  What
exactly do you expect that program to do?  Lets look at it.

You have a local variable of type FILE *.  You assign the value
stdprn to it.  Then you pass that value (ie, stdprn) to fclose.
Now, what would you expect to happen if you had said:

        fclose ( stdout );
        fprintf ( stdout, "help, I can't talk anymore!\n" );

I would expect it to not be able to talk and thus it would say nothing.

Now, recalling that this is C and not some hypothetical language we
are discussing, how is fclose supposed to know the difference between

        fclose ( stdprn );

and

        foo = stdprn;
        fclose ( foo );

?????????

***** SPOILER WARNING *****

It isn't.

--
Steve Nuchia        | [...] but the machine would probably be allowed no mercy.
uunet!nuchat!steve  | In other words then, if a machine is expected to be
(713) 334 6720      | infallible, it cannot be intelligent.  - Alan Turing, 1947