FBSD 4.8/GCC
////////
C-CODE:
////////
char c;
while ( 1 ) {
read(0, &c, 1); printf("%02x ", c);
close(0); open("/dev/stdin", O_RDWR, S_IRUSR|S_IWUSR );
}
//////////
Question:
//////////
this is confusing to me. 'open' doesn't reopen 'stdin'
('errno' keeps getting set, and no new characters are
ever read - after the 1st one).
i have a function that opens, reads, and closes a file.
i would like to use this function to read a file piped
from 'stdin' as well as from disk. the problem is i
can't re-open 'stdin' after the file reading function
closes '/dev/stdin'.
is there any way to "reset" /dev/stdin so that
it functions normally after being close(2)'d? 6 13673
On 10 Oct 2003 13:06:23 -0700, i1*******@yahoo .com (chad kline) wrote: FBSD 4.8/GCC
//////// C-CODE: ////////
char c;
while ( 1 ) {
read(0, &c, 1); printf("%02x ", c); close(0); open("/dev/stdin", O_RDWR, S_IRUSR|S_IWUSR ); }
Unfortunately, it is not standard c. Neither open nor close are
defined in the standard library.
<<Remove the del for email>> i1*******@yahoo .com (chad kline) wrote in message news:<47******* *************** ****@posting.go ogle.com>... FBSD 4.8/GCC
actually, i have a better example of what i am trying to do.
i have searched "everywhere " for the solution, and have seen
the question asked in many places, but without any clear answers.
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
////////////////////////////////////////////////////
int main(int argc, char* argv[]) {
char c, fd2, err;
fd2 = dup(0);
while ((err = read(0, &c, 1))) { // read pipe.
printf("R: %i:%i:%02x\n", errno, err, c);
} errno=0;
err = dup2(fd2, 0);
printf("2: %i:%i:%02x\n", errno, err, c);
errno=0;
while ((err = read(0, &c, 1))) { // read keyb.
printf("R: %i:%i:%02x\n", errno, err, c);
}
exit(0);}
////////////////////////////////////////////////////
this doesn't work - what needs to be done to make it work?
if i avoid all 'dup's and just continue to read stdin after
reading the pipe, the 2nd read just keeps reading the last
char of the piped file (generating errno's).
i want to make stdin read the keyboard after reading the pipe.
i don't want to use 'streams' (fopen, freopen, etc). i1*******@yahoo .com (chad kline) wrote in message news:<47******* *************** ****@posting.go ogle.com>... FBSD 4.8/GCC
this defines much better the problem
i am trying to solve. it would be
better if the '/dev/tty' stuff
wasn't necessary.
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
/////////////////////////////////////////
int main(int argc, char* argv[]) {
char c; int n, fd;
while ((n = read(0, &c, 1))) // read pipe.
printf("PIPE: %02x:%i\n", c, n);
fd=open("/dev/tty", O_RDWR, 0600);
printf("OPEN: %i:%i\n", errno, fd);
dup2(fd,0); close(fd);
while ((n = read(0, &c, 1)) < 1 ); // wait keyb.
printf("KEYB: %02x:%i\n", c, n);
exit(0);}
///////////////////////////////////////// i1*******@yahoo .com (chad kline) wrote in message news:<47******* *************** ****@posting.go ogle.com>... FBSD 4.8/GCC
i apologize for the several posts,
but since it takes 10 hours or so
to post, i was able to figure some
things out, and think it's good
knowledge to have in the DB. it
seems to be a question without
many good answers (not that the
one i found is "good", not sure).
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
///////////////////////////////////////////////////
int main(int argc, char* argv[]) {
char c; int n;
while ((n = read(0, &c, 1))) // read pipe.
printf("PIPE: %02x:%i\n", c, n);
dup2(1,0);
while ((n = read(0, &c, 1)) < 1 ); // wait keyb.
printf("KEYB: %02x:%i\n", c, n);
exit(0);}
/////////////////////////////////////////////////// i1*******@yahoo .com (chad kline) wrote: i1*******@yaho o.com (chad kline) wrote in message news:<47******* *************** ****@posting.go ogle.com>... FBSD 4.8/GCC i apologize for the several posts, but since it takes 10 hours or so to post, i was able to figure some things out, and think it's good knowledge to have in the DB. it seems to be a question without many good answers (not that the one i found is "good", not sure).
#include <errno.h> #include <stdio.h> #include <fcntl.h> #include <unistd.h>
But still it's hopelessly off-topic in comp.lang.c, as you are dealing
with non-standard extensions to the C language.
To echo Jack Klein:
Ask in a group that supports your particular compiler/OS combination.
<SNIP>
Regards
--
Irrwahn
(ir*******@free net.de) This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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